The Pallava 'Mahishasuramardhini'

Over 2 weekends in September 2024, we visited Mamallapuram, as part of the Tamil Heritage Trust's Docent Training Practical sessions. Although, over the years, I've visited Mallai, at least 20 times, on my own and with my friends, this was an entirely different experience.

Badri, Gopu, Ravi, Vallabha and Shivshankar Babu of THT, gave an all too new and additional dimension to the monuments and the sculptures within. What I gained in the process, is not just a fresh insight or a different perspective but an entire additional layer of information, analysis and inference that completely changed my perception of these monuments so far.

Viewed from this fresh angle, what struck me the most, filling me with amazement at Pallavas creativity, is the plethora of Mahishasuramardhinis at Mamallapuram.

Artistically, they are heads and shoulders above most of the Mahishasuramardhinis elsewhere. Over and above the perfect anatomy, grace and rhythm of the Devi and her entourage, or the dynamic quality of the panels including the Asura and his men - these sculptures seemed to whisper to me, something that we are struggling to understand and come to terms with even today.

The identification that I feel with these depictions is so complete, that I was forced to look into the Puranic, Iconic, Historic and sculptural attributes of this form of the Devi, before I could articulate my own personal findings here.

Ellora Cave 16 and Ekambareshwarar Kanchipuram - Harihara Subramanian(Shutterbug Iyer) 

One of the most magnificent and formidable Goddess of the Hindu pantheon, Mahishasuramardini

is worshipped as a supreme power under the Shaktham sect of Hinduism.

Endowed with incredible cosmic super powers, her mission is to destroy evil and establish Dharma. It is her epic battle against the bull-demon Mahishasura that gives her the name. Mahiṣāsuramardinī is an epithet of Durga, literally meaning, "the slayer of the demon Mahisha"

Among Puranas, she is referenced in Agni Purana, Markandeya Purana, Matsya Purana and Vishnu Dharmottara Purana. Among Agamas she is mentioned in The Shakta Agamas, also known as Tantras, that focus on the goddess Shakti or Devi, and include the Tripura Upanishad and the Devi Upanishad. She is also mentioned in the epic Mahabharata.

Her most prominent reference is in Devi Mahatmiyam, a portion of the Markandeya-purana, written around 5th Century CE. It is the first such text that revolves entirely around the figure of the Goddess (Devi) as the primary deity.

The work has been passed down as a self-contained text that is memorized and recited, word for word, as part of the religious practice of those Hindus who worship Devi as the highest divinity.

The Legend...

Mahishasura, the demon, was born as a union of Rambha and a she buffalo (Mahishi) and consequently was a half man and half buffalo. The mighty demon was rendered more powerful as a result of a boon from God Agni, according to which he could be killed only by a woman. He managed to wreak havoc in heaven by chasing away all Gods from there. 

All the Gods then approached lord Vishnu and lord Shiva who were aware that only a woman could kill Mahishasura. They decided to create a Goddess out of the collective powers or 'Tejas' of all the Gods  

Radiant energy emanated from all of them and this dazzling energy coalesced into a brilliant whole which seemed like a never-ending mountain of fire. The mountain of radiant energy transformed into the feminine form of the incomparable Devi – the Adishakti (the primordial being and/or energy).

She was endowed with all divine weapons including the conch (shankh), the spear, the wheel, the lotus, the arrow and the mace. Her trident came from Shiva, Sudarshana Chakra from Vishnu, the Lotus and the kamandlam of Holy water from Brahma, the Lion from Himalayas and bows and arrows from Vayu. The Goddess, filled with combined power and anger of all the Gods, was fierce to behold and her very sight scared the demons. 

Mahishasura waged a valiant fight against her and assumed the form of a buffalo, a lion, a man carrying a sword, an elephant and lastly again a buffalo. The battle raged for 9 days and finally the Goddess was able to pin down Mahishasura and chop off his head. The Gods, rid of the demon, showered the Goddess with innumerable praises and with reverence, prayed her to appear every time they were in need of her. Granting the same to the Gods, she disappeared to appear again when called with devotion.

Folk Art representations across India - From the Net

The Iconography...

Mahishasuramardini is normally depicted as a warrior figure with elaborate jatamukuta and her legs spread out on either side of the lion, similar to a horse rider with either 8 hands or 10 hands, and is mostly shown to be fighting the Mahisha.

Baijnath temple - Himachal Pradesh, Baital-Deul temple - Odisha, Aihole - Karnataka 
Harihara Subramanian(Shutterbug Iyer) 

According to silpasastra, especially from the Vishnumahottara, the Goddess should have ten hands and three eyes, she should wear jata-mukuta on her head with a Chandra-kala (moon). The colour of her body should be like Atasi- flower and eyes should resemble nilotpala. She should have high breasts and in her waist, there should be three bends. In her right hands she should hold Trisula, Chakra, Khadga, bow etc and in her left hands pasa, ankusa, parashu, bell etc. The lion should be at her feet and a severed buffalo demon head should also be there. The right leg of devi should be on the lion and the left leg on the injured but terrified looking Asura who is coming out of the severed body of the buffalo. 

However, normally she is depicted with 8 or 10 arms, with other variations of 4, 6, 12 or more arms. In the eight arms of the Goddess are seen in a clockwise direction, disc, trident, arrow, sword, darjani mudra, the tuft of the hair of the demon, shield and a bow. 

Art Historians have noted that the no of arms is often dependent on the iconography of the Mahishasura and the dynamic composition thus formed.

Mahishasura himself is depicted in 3 major forms. 

• As a hybrid, where his body is human and head that of a buffalo;
• Where he himself is emerging from the severed head of a buffalo;
• A demon in complete animal or theriomorphic form.

From simply killing the demon, specific details emerged over a period of time, like thrusting a trident or lance into his body, squeezing his head or lifting his rear half by his tail etc.

This development of the iconographic portrayal of the Mahishasuramardhini with her lion vahana and the Mahishasura saw a marvelous development in the sculptural art across India, moving from earlier static images to animated dynamic forms which were stand alone or part of narrative panels.

 

Earliest depictions...

Mahishasuramardinis found in Nagar (1stc. BCE – 1stc.CE ), Mathura (c.200CE) L.A County Museum.Gurajala in Guntur district, Andhra Pradesh (4thc CE) - From the net.

In the pre Kushana and Kushana era, Mahishasuramardinis are simple in form and lack the complexities of the ‘Devi Mahatmya’ iconographic descriptions.  The devi wears the typical Kushana era styled dhoti and girdle, and carries a sakti (spear) and trisula. The important aspect here is that, the fight between the Devi and the Mahisha is more bare handed with less use of weapons. The Devi has no attendants and even her vahana simha is absent some of the times.

One can also easily trace the evolution of the sculptural form right here, although the core idea is borrowed from the Puranas.  

Later Developments...

Udayagiri Caves, Gupta Period (401 CE), Nalanda, National Museum (600-700 CE),

Chandra Gupta II Coin (375 CE) - From the net

Beside stone representation, there were depictions in Bronze and Gold coins too. In the Nalanda representation, one can see  an iguana below her, which got associated with the Devi in Sakta worship, followed in the Mauryan-Sunga period figures of Mother Goddesses seen with alligators.

The late Gupta period also show her as the Simhavahini where she is four armed, sitting on a lion in Padmaasana.

A few famous Depictions... 

1. Betal Deul Temple in Odisha - The Mahisasuramardini sculpture here is depicted with eight hands. The goddess is seen to be piercing the theomorphic demon with trisula. Her other hands hold weapons like sword, shield, snake etc. A fierce lion is seen to be biting the demon on his hand.  

The Mahisha in the front hiding the lower part of the Devi, her proportions, grace, detailing and the expression on the Devi's face make this one of the best artistic representations through the ages.

2. Durga Temple in Aihole, Karnataka - A full relief panel in classic tradition, this 8 armed Durga is mesmerizing in her grace. Statuesque in her dignity and unperturbed in her demeanor, her face is glowing with peace and contentment. She is not only a young lady, full of charm with high breasts and wide hips, wearing ornaments but also a warrior on battle ground as seen by the weapons and intricately carved armour in her hands. The valour depicted here is truly one of a kind. 

3. Rani ki vav, Gujarat - One of the most exquisite of all Mahishasuramardinis, Goddess Durga in this Solanki sculpture is killing the Mahisha demon in both animal and human form. She is the most ugra of forms and has sixteen hands, yet her expression reveals her innate calmness and inevitable acceptance of her intent and purpose. 

The Pallavas...

Some of the most exquisite Mahishasuramardinis have been created by Pallavas not only in Mallai, but in Kailasanathar Koil in Kanchipuram and other temples as well.

Kanchi Kailasanathar Koil (me) and Panamalai Durga (Rajavel)

Epitome of anatomical grace and beauty, the Pallava Mahishasuramardhini, is personification of a woman, in her head gear, her ornaments, her posture and her expression. In her dynamism and animation, she does not imitate her male counterpart. Her stance, her pose and her battle is her own , fought on her terms.

The sculptural beauty ofcourse peaks with the the 2 narrative panels in Mallai.

Mahishasuramardhini Mandapam, Mallai (me)

This most majestic and well-preserved panel with its fluidic movement and detail, is almost like an animated presentation.

One of the best examples of Pallava art, in the war scene, the goddess appears with eight hands riding a fierce-looking lion. She is holding a khadga(sword), dhanush(bow), bana(arrows), ghanta(bell) in her four right hands. Her four left hands display pasa, sankha, and dagger. An attendant holds a chatra (parasol) over Durga's head. 

She is in the battlefield with her army of female warriors and ganas (dwarfs). She is shown attacking, with arrows, the demon Mahisha, causing him to retreat with his followers. Mahishasura is armed with a gada (club). 

This image of Mahisasuramardini is also unique because, unlike in the majority of the images, the asura appears in his anthropomorphic form, which is his only depiction. There is no decapitated body of the buffalo. On the other hand, he is given equal weightage in the composition, with his stance, a clear indication of retreat and impending defeat.

She is clearly the aggressor, the one charging forward, sitting astride her lion. Her hands are in action, pointing the sword, holding the bow and pulling out arrows and managing all her other weapons. Yet even in this path of destruction and mood and ethos of anger and aggression - her feminine qualities are all too evident. In her attire, demeanour and expression, there is no attempt to imitate the male. She is unique and different and that is displayed in every chisel stroke that has shaped her.

Panel outside Athiranachanda Cave Temple, Mallai (me)

On a separate boulder in front of the Athiranachanda cave temple is this magnificent panel depicting Durga as Mahishasuramardini. One of the best specimens of Pallava art for its aesthetic, dynamic and vivid portrayal of the fight scene and its partcipants, this is considered by Art Historians to be next in sequence, to the Panel above, as here the Goddess has completed annihilation of the demon army, dismounting from her mount over to a lotus pedestal. 

Here the Goddess has 6 arms, carrying all her weapons and she is in the process of alighting from her lion mount. The asura has accepted defeat and is retreating and his demon army is being chased and vanquished by her army of Ganas. Again her feminitity, her prime trait, is supreme. While almost every other figure in the panel is charging or retreating in a violent pose, she is calm. Her mission accomplished, she is sure and secure in her skin.

What is unique about the Pallava Mahishasuramardhini ?

A question that is bound to haunt any art connoisseur is - 'what is it that makes the Pallava depictions of this Goddess unique?' They have something extra, something special, that sets them apart from the hundreds of other depictions all across India, through the ages.

Thorough scrutiny of the sculptural details and attempting to understand their essence, led me to realize that for Pallavas - Durga is a Devi, a Goddess, a woman first and foremost. 

Circumstances may have led her to take on a man's role and don his mantle. She may, well be, out of a traditional womans's role here; not a nurturer, but a destroyer. Her modus operandi is that of the men around - after all she is vanquishing a male prototype - an able bodied, strong, asura - no less. But even in these contradictory circumstances where the ethos is fully male, her femininity, is intact. She is innately a woman - a dignified, graceful, charming entity. She is capable of rising to any occasion, to win her battle in a male dominated scenario without compromising her identity.

The Pallavas thus have embodied the principles of the Puranas where  Mahishasuramardini is the formless divine (nirguna) who assumes form (saguna) to re-establish Dharma or the moral order. In  her saguna she is feminine, she is independent, and she is timeless. As Adishakthi, she feels no need to either merge or compromise her persona, with that of her counterpart.

Only in the Pallava depictions, do we see this very clearly, not only in her physical and anatomical attributes, but her charm, grace and expression of calmness bely her actions. Through the actions of violence, aggression and destruction, she is timelessly embodied as this quintessential woman. Her femininity is her main trait and that is what sets the Pallavas creations apart.

Reiteration of the feminine form - Mallai (me)

It is this essence that makes Pallava Mahishasuramardhini, a role model for the modern woman. Shorn of  her safe physical boundaries and traditional roles, the modern woman finds it very difficult to hold on to her identity.

I have repeatedly questioned myself, both about the way I dress and project myself and about the adoption of a competitive, aggressive non feminine attitude. On one hand, am I thrusting my femininity in the face of others? Do i need to be more unigender in my representation? On the other, am I too loud, too fierce, too male in my stance and attitude? Am I losing my identity in the process?

These are questions faced by every modern woman, trying to come to terms with her ethos and find her true identity and hold onto it, no matter where she may work, or with whom or for that matter, the very nature of her work.

We may well have entered the male bastions and taken on, at least, some of their roles, but in our overall equation with them and society at large, we are women and would like to remain so.

This total acceptance of my persona, my identity, is what the Pallava depictions were urging me to do with their whispers. To be who I am, with no apologies whatsoever. I am a woman, first and foremost. Where I perform or what I choose to do, can not alter this basic fact. I need not always celebrate my gender, but I dont need to hide it either, nor apologise for it.

Timeless art can, not only enhance our aesthetic sensibilities, but at times, also teach us basic life lessons. 

 

A talk by Nobel Laureate Dr. Brian Kobilka

When I came across a flyer for the above, கொஞ்சம் ஆர்வக் கோளாறுலேயும் கொஞ்சம் அசட்டு தைரியத்துலேயும், registered immediately. 

- ஆர்வக் கோளாறு - when else will i get a chance to attend a Nobel Laureate lecture in person?

- அசட்டு தைரியம் - the speaker is bound to know the average knowledge base of the audience. After all it's a public forum.

Came the day, I was happy to be accompanied by Gopu! (who I was sure would understand more than me & may not be averse to a few explanations.)

Let me confess - I left Chemistry and all other Science subjects behind in High School, all of 40+ years back. Am not very updated on current happenings in the Practical Scientific world, leave alone Research! In fact I was happy, Dr. Kobilka is an American and I could at least pronounce his name properly and would understand his accent. (The few times in my life, when my Hollywood addiction is put to good use.)

IIT and Vallabha

This lecture was arranged by IIT Madras under their 'Eminent Speaker Lecture Series' at Music Academy, Chennai. The topic for the talk was 'From Fields to Frontiers: The Journey of a Physician - Scientist'.

The Talk....

At the outset, it was amusing to hear Dr. Kobilka say, 'This was his largest audience and he was nervous!' If most of the audience was like me - he had no idea, how nervous we were.

But surprisingly he started on a non scientific note. Highlighting his background, his academic journey, the various institutes he had associated with etc. This put the audience, at least me - at ease. I was all ears & comprehending. Slowly Science crept in, but I was still in sync - Thanx to the simple Graphic slides!

Dr. Kobilka's Early life....

(Growing Up In Little Falls, Minnesota)

Born into a baker's family in Little Falls, Dr. Kobilka said the town was hardly 8sq miles in area (No more than 3 miles in any direction) with a max population of 7500. The 3D map showed the relative locations of various buildings in the town and his first job was slicing bread in his father's bakery. It was a family owned business run by his grandfather.

He attended St. Mary’s elementary school through the eighth grade then moved onto Little Falls High School. His interest in science started with wanting to become a physician. Alas! there was no usual noble thoughts behind this, but the mere impression that local physicians were given a lot of respect.

His favorite classes in high school were math, physics, chemistry and biology. (Fortunately I had Maths in common with him!)

Undergraduate Years....

After school, he entered the University of Minnesota, Duluth to prepare for medical school, in 1973.

In his very first term, he was lucky enough to meet both his future wife (Dr. Tong Sun Thian) and his mentor Professor Conrad Firling. He met Dr. Tong the very first week, in the Biology Lab, and they seem to have been together since.

Professor Conrad Firling, was a  biology professor, who was willing to take undergraduates into his lab to work on projects in developmental biology. Under him Dr. Kobilka learnt

- first to wash glassware, in a lab, properly.

- later to develop an organ culture medium for studying the salivary glands of some insects and their chromosomes.

(Science was beginning to creep in & I've no idea what those insects were!)

He also worked on a summer project with Professor Robert Carlsen, an organic chemist and this sowed the seed for a growing interest in basic research.

Majoring in Biology and Chemistry, he applied to ten medical schools, but was selected only in 2. Fortunately for him, one of them was Yale and he moved there from Duluth. 

Yale University Medical School....

At Yale, as part of their curriculum, all medical students were required to write a thesis based on original research. 

Dr. Kobilka's very first research project involved dengue fever, on which he worked, through a summer in a lab in Malaysia, involving both field and bench research.

For his thesis project, he worked with Professor Denis Knudsen, a virologist, studying the genetic diversity of rotavirus, a common cause of gastroenteritis in children.

According to him, both these projects were not successful, because they were short termed and gave no fresh scientific insights, into their respective domains. Their only benefit was reinforcing the passion for pure research in him.

After his first year of Med School, he married Tong Sun, who was not a Doctor yet.

Clinical Training At Barnes Hospital...

Owing to financial constraints, a career in research was not an immediate option and Dr. Kobilka decided on a residency in internal medicine at Barnes Hospital, affiliated with Washington University School of Medicine in St. Louis, Missouri, for 3 years.

Dr. Kobilka explained that The Human nervous system can be divided into two functional parts: the somatic nervous system and the autonomic nervous system. The autonomic nervous system regulates many of the internal organs through a balance of two aspects, or divisions. The two divisions of the autonomic nervous system are the sympathetic division and the parasympathetic division. The sympathetic system is associated with the fight-or-flight response, and parasympathetic activity is referred to by the epithet of rest and digest. Homeostasis is the balance between the two systems. At each target effector, dual innervation determines activity. For example, the heart receives connections from both the sympathetic and parasympathetic divisions. One causes heart rate to increase, whereas the other causes heart rate to decrease.

During his training at Barnes, his interest in intensive care medicine, led him to continuously take rotations at the 3 intensive care units - medical, pulmonary and cardiac. Here he found that, patients were typically unstable and required urgent medication

-  to regulate their heart rate and blood pressure

-  to control pain.

He went onto mention that these medications acted on GPCRs (G protein coupled receptors), which are of several types.

Those regulating BP and pulse are called adrenergic and muscarinic receptors, while those controlling pain are opioid receptors.

By now, I was at sea and slowly drowning. The talk was going above my head. I, ofcourse, went back and googled and somewhat surfaced from deep water. Sharing some of that here....

What are GPCRs?

GPCRs are proteins located in the cell membrane that binds extracellular substances and transmits signals from these substances to an intracellular molecule called a G protein (guanine nucleotide-binding protein). 

GPCRs are found in the cell membranes of a wide range of organisms, including mammals, plants, microorganisms, and invertebrates. There are numerous different types of GPCRs—some 1,000 types are encoded by the human genome alone—and as a group they respond to a diverse range of substances, including light, hormones, amines, neurotransmitters, and lipids.

Nearly every function of the human body, from sight and smell to heart rate and neuronal communication, depends on G-protein-coupled receptors (GPCRs). Lodged in the fatty membranes that surround cells, they detect hormones, odours, chemical neurotransmitters and other signals outside the cell, and then convey their messages to the interior by activating one of several types of G protein. The G protein, in turn, triggers a plethora of other events. The receptors make up one of the largest families of human proteins and are the targets of one-third to one-half of drugs. Working out their atomic structure will help researchers to understand how this central cellular-communication system works, and could help drug-makers to design more effective treatments. 

The Net

A GPCR is made up of a long protein that has three basic regions: an extracellular portion (the N-terminus), an intracellular portion (the C-terminus), and a middle segment containing seven transmembrane domains. 

Beginning at the N-terminus, this long protein winds up and down through the cell membrane, with the long middle segment traversing the membrane seven times in a serpentine pattern. The last of the seven domains is connected to the C-terminus. 

When a GPCR binds a ligand (a molecule that possesses an affinity for the receptor), the ligand triggers a conformational change in the seven-transmembrane region of the receptor. This activates the C-terminus, which then recruits a substance that in turn activates the G protein associated with the GPCR. Activation of the G protein initiates a series of intracellular reactions that end ultimately in the generation of some effect, such as increased heart rate in response to epinephrine or changes in vision in response to dim light.

The existence of GPCRs was demonstrated in the 1970s by American physician and molecular biologist Robert J. Lefkowitz. Lefkowitz shared the 2012 Nobel Prize for Chemistry with his colleague Brian K. Kobilka, who helped to elucidate GPCR structure and function.  

In 1984, after his residency, Kobilka applied for cardiology fellowships, and he was particularly interested in the program with Robert Lefkowitz at Duke University in Durham, North Carolina. It was the premier lab studying receptors for adrenaline, which had become a model system for all hormone receptors. This gave him the opportunity to explore basic research in an area relevant to cardiovascular and intensive care medicine. 

It is interesting to note that Dr. Kobilka, never became a cardiologist.

With his young family started in St. Louis.

Fellowship Training At Duke University...

Joining the Lefkowitz lab, Dr. Kobilika found that, almost everybody there, seemed to know more than him and he was yet to familiarise himself with the research work being done there and the techniques they were using.

When Kobilka joined, the lab was just starting to think about how to clone the gene for the β2 adrenergic receptor (β2AR)  and determine its genetic sequence. But the receptor was produced in such small amounts that the team was only able to collect enough protein to work out a few scraps of its likely genetic sequence. 

From now on, we were in the midst of Scientific talk about Scientific research, and there was a lot, that I did not understand or misunderstood. I tried correcting a lot of my misunderstandings with further reading, but there may still be errors here - a direct result of my limited understanding.

Kobilka, joining the programme, decided to construct a library of mammalian genomic sequences and screen it with the scraps of sequences they had. This would pull out longer clones that could be pieced together to reveal the full sequence. However, when the team stitched together the receptor sequence, it had a real Eureka moment: several strings of amino acids that are typically found in cell membranes showed that the receptor snaked through the membrane seven times, just like rhodopsin, the light-detecting receptor in the retina that was also known to activate a G protein. 

It was a surprise that, these receptors looked alike,  one turned on by light, and the other by a hormone.

At the time, about 30 proteins were known to turn on G proteins, and they concluded that it was a whole family of look alike receptors. This family became known as seven-transmembrane receptors, or GPCRs, and is now known to have nearly 800 members in humans. 

Dr. Kobilika, then, wanted to understand receptor structure and how the receptor worked in molecular detail. Thus the project extended to obtaining a crystal structure. Several years earlier Deisenhofer and Huber had obtained the first crystal structure of a membrane protein, proving that membrane proteins could be crystallized and demonstrating the value of protein structure in understanding mechanisms. However, the photosynthetic reaction center was a naturally abundant protein that could be obtained from bacteria. In contrast, even in lung tissue, where the β2AR was most abundant, it represented a very small fraction of membrane proteins.

Stanford University...

Around this time (1989), at Stanford, Professor Richard (Dick) Tsien, had just moved from Yale, and was building a new Department of Molecular and Cellular Physiology in the Beckman Center. Dr. Kobilka was offered a junior faculty position, which he accepted and moved to Stanford. To make ends meet, he moonlighted as a doctor in the emergency department at weekends. 

In the lab they focused on two objectives: 

- understanding the structure and mechanism of activation of the β2AR and 

- determining the physiologic role of specific adrenergic receptor subtypes. 

Cloning and pharmacological studies had identified 9 adrenergic receptor subtypes coded by 9 different genes: three βARs, three α1ARs, and three α2ARs. The drugs available at that time were not sufficiently selective to allow assignment of specific functions to each receptor subtype. 

Dr. Kobilka wanted to see what the receptor looked like in three dimensions using X-ray crystallography, in which a beam of X-rays is fired at a protein crystal and the resultant diffraction pattern is used to reveal the arrangement of its atoms. However to produce an intelligible X-ray diffraction pattern, one first needed to crystallize the receptor- a formidable process of packing millions of identical copies of protein so tightly that they form a solid that looks like a microscopic shard of glass. 

Working out the conditions that will allow a protein to crystallize can take years, and membrane proteins such as GPCRs are the hardest of all: they must be coaxed out of the membrane intact, but it is the membrane that holds them in shape. GPCRs are also constantly shifting into various states, and most are expressed in very low quantities. To collect enough β2AR protein, one had to express about 100-1,000 times the levels at which it is normally produced in a cell. Later, they also used fluorescence spectroscopy, one of the most sensitive biophysical techniques, to investigate receptor structure.

Gopu & Rajagopal V

As the years rolled by, Kobilka's lab was carrying out various biochemistry and biophysics experiments aimed at getting to know the β2AR more intimately, and he was inching forwards in expressing and purifying the protein. But there were a lot of setbacks. They found that the GPCRs have big, floppy loops inside and outside and the receptor writhes and squirms, adopting a variety of levels of activation, which only made crystallization more and more difficult.

 

Finally, in late 2004, the group managed to grow tiny crystals, too small to be analysed at Stanford's synchrotron facility. Based on the suggestions of Gebhard Schertler, a crystallographer, Kobilka took his samples to the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, which had the tightly focused beamline needed to analyse such small crystals. 

But the crystals diffracted to a resolution of only around 20 angstroms - so low that there was no discernible image. A resolution of about 4 A is needed to see the organization of individual atoms.

Further frustration followed, when the team couldn't get the crystals to grow any bigger or diffract any better. The receptor's changeable activation states and floppy segments, made it very difficult to trap all the proteins in an identical conformation. The team realized that they'd have to do something radical: chop off the loose ends, and either anchor the loop in place with an antibody or replace it altogether with a protein known to crystallize well.

The two approaches....

In 2005 Dan Rosenbaum and Søren Rasmussen, two very talented and intrepid postdoctoral fellows, joined the lab with the goal of crystallizing the β2AR. Søren and Dan took two different approaches to generate better quality crystals of the β2AR. 

Søren identified antibodies that bound to a particularly flexible region of the receptor and Dan used protein engineering to replace the same region of the β2AR with T4 lysozyme (T4L), a highly crystallizable soluble protein. During 2006 crystals were obtained using both approaches combined with a newly developed lipid-based media known as bicelles consisting of a mixture of lipid and detergent. Initial crystals of the β2AR-Fab (3.4A) and the β2AR-T4L (2.8A) fusion protein complex, both diffracted to below 4A. 

A trio of papers marked a milestone in structural biology, and intensified aggressive research into GPCR structures.

But these GPCR structures had been snapshots of receptors in an inactive state. To really understand the receptor's workings, researchers needed to see it as it was being activated by a ligand and turning on the G protein. This project was even more technically daunting than the last. The protein complex was too big to hold in the fatty scaffold; the G protein kept falling off; and this time, the extracellular part of the receptor wouldn't sit still for crystallization. 

Dr. Kobilka reached out to all manner of experts for help and the various groups developed a detergent for stabilizing the receptor with its G protein; a lipid scaffold that could support the complex; and an antibody that could hold it together. And then they tested thousands upon thousands of crystallization conditions and ways to engineer the protein.

Finally, after another 5 years, they solved it and got a resolution of 3.2A revealing a tangled molecular threesome: β2AR with a ligand clasped at one end and the G protein nested up on the other. 

The β2AR-Gs crystal structure was published in 2011 together with two companion studies using single particle electron microscopy and deuterium exchange mass spectrometry to characterize the dynamic aspects of this complex. These combined studies provided unprecedented insights into GPCR signaling at a molecular level.

It was for this pioneering work, that, The Nobel Prize in Chemistry 2012 was awarded jointly to Robert J. Lefkowitz and Brian K. Kobilka "for studies of G-protein-coupled receptors."

Brian. K. Kobilika receiving his Nobel Prize from H M King Carl XVI Gustaf of Sweden
at the Stockholm Concert Hall on 10th Dec 2012.

After this climax, there were 2 more sections of Epilogue...

Why 20 long years?

Gopu R

According to Dr. Kobilka, this entire research took almost 20 years mainly because

-  It was a new field and they almost started from scratch

-  They had to learn how the receptors are built, how they transmit signals over the membrane and how they are regulated

-   Purifying the Protein, Crystallizing it to a high level of resolution in both their active and inactive stages, ensuring their stability, even when drawn out of their shells - all took their own time.

-   The mechanisms for diffraction were also not so developed and Computer Docking was in its developmental stage.

The entire team managed to sustain their interests, hopes and irrational optimism through these years because

-  They constantly achieved incremental advances & successes that kept their hopes alive.

-  They were simultaneously learning so many new things about the Human nervous system, especially with respect to the GPCR.

-  The nurturing scientific & academic environment of which they were a part.

-  Their family and friends and the entire scientific fraternity and last but not the least, his wife, who worked with him every step of the way, supporting him both professionally and personally.

-  His own temperament, love for his work and the sheer joy he derived in research.

His post Nobel Work....

I had very poor understanding of this section and the Graphs shown.

This part of the lecture is paraphrased in my own words.

Along with a team Professor Brian Kobilka, discovered the drug called PZM21 after evaluating some three million different compounds. His research is mainly aimed at finding an alternate to Morphin as a painkiller.

Morphine, derived from the opium poppy, works by acting on a receptor in the brain that reduces pains, but it also affects a different receptor that can lead to fatal breathing problems in the event of an overdose. But PZM21, which so far has only been tested on mice, appears to act on the first receptor to about the same level as morphine without significantly changing the second one.

It also caused less constipation than opiate drugs, a factor that limits how much of the drug can be given. The new drug dulls the feeling of pain in the brain because it has a “potent, selective and efficacious” effect on the brain receptor involved in the sensation of pain, without dangerous side effects.  

Studied against Morphine, on mice, PZM21 did not appear to affect their breathing and the painkilling effect of PZM21 lasted for up to three hours, “substantially longer” than the maximum dose of morphine. The “constipating effect” was also “substantially less than morphine” and the mice did not show signs of addiction.

Morphine addiction is a result of the activation of the brain’s dopamine reward circuits. When this happens in mice, they tend to run about a lot. But PZM21 had “no apparent effect on locomotion”.

Vallabha Srinivasan

What is PZM21?

PZM21 is an experimental opioid analgesic drug that is being researched for the treatment of pain. It is claimed to be a functionally selective μ-opioid receptor agonist which produces μ-opioid receptor mediated G protein signaling, with potency and efficacy similar to morphine, but with less β-arrestin 2 recruitment.

In tests on mice, PZM21 was slightly less potent than morphine or TRV130 as an analgesic, but also had significantly reduced adverse effects, with less constipation than morphine, and very little respiratory depression, even at high doses.  

Dr. Kobilka concluded his lecture, by thanking his team & family and introducing them via pics.

Rajagopal V

My own take aways from the lecture

- As a speaker Dr. Kobilka was not flashy, aggressive or imposing. Rather soft spoken, his talk was delivered like a classroom lecture in a low sonorous voice.

- Yet he was very impressive. Kept the audience fairly hooked.

- The 2 main aids to this were - His presentation slides, that were simple, clear and precise and 

- His own unbridled passion for his work that came through even when he was describing complex and inanimate Protein structures.

Lastly, I must read up, atleast about Basics, before attending such lectures, if I want to optimise the experience.

Acknowledging Vallabha, Vidya, RV, Jayakamala & their kids - 

என் சக ஆர்வலப் பயணிகள்!

A big Thank you to Gopu, who made this an enjoyable experience and matched my every step in weathering sudden winds, rains, pot hole filled roads and Chennai peak hour Traffic to attend this lecture. The upturned umbrella and his valiant attempt to turn it back remains etched in my mind!

It seemed like a metaphor.

Standing exposed in ur ignorance, as science rains all around u.

Thankfully, he straightened the umbrella soon!

Buddhist Tales across Visual Media #1 Taming of Nalagiri

I first came across, visual Depiction of Buddhist Tales, in the Amaravati Gallery at Chennai Museum.

Buddhist art normally depicts

- Episodes and scenes from Life of Buddha

- Jataka Tales

across paintings and sculptures.

Because

-  I had read most of the Buddhist and Jataka tales (at least the important ones)  

-  Gopu was extremely lucid & patient in his explanations
I was mesmerized, to say the least of it. 

True to my nature, I went back a couple of times to the Gallery on my own, admiring and understanding, apart from other things, the grammar involved in depicting a story, visually, in such a small area.

Jataka Tales... (To the uninitiated...) 

The Jātaka Tales are a voluminous body of literature native to the Indian subcontinent which are mainly concerned with the previous births of Gautama Buddha in both human and animal form. A Jataka tale relates an episode in a past life of the Buddha. 

There is always a character in the story who is identified as the Buddha-to-be. He is often (but not always) the hero, usually referred to as Bodhisattva, because he is yet to attain his enlightenment.

Many stories illustrate general Buddhist moral ideals, including honesty, wisdom, kindness, generosity and detachment. Usually it is the Buddha who narrates the story of his past life, in order to explain something about a situation or character that he or his followers have encountered.

 

Bodhisattvas come in many forms of life. Swans, Deer, Nagas or Snakes, Monkeys, Elephants, and of course Human beings of a lesser order of enlightenment.

Jataka stories were depicted on the railings and torans of the stupas . The circular Medallions in the Chennai Museum are remains from the Stupa at Amaravati.

Medallions from the Amaravati Stupa - Chennai Museum

Amaravati Art...

The Amaravati school of art and sculpture is supposed to have flourished in the second century BC especially in the second half.

Satavahanas were the first patrons of this school.

The Major Features of this school include 

- The 'narrative art' - The medallions are carved in such a way that they depict an event in a sequential manner.

-  In human, animal, and floral forms, there is a sense of movement and vitality, as well as profound and serene naturalism.

- Amravati, Nagarjunikonda, Goli, Ghantasala, and Vengi are notable locales where this style flourished.

I don't know if it was the fact that an ELEPHANT was the central character, portrayed in all its grace, Majesty and grandeur; or the story itself, which was the allure; 

But I quickly zeroed in on these 2 

- Nalagiri - The Taming of an elephant (Story from Life of Buddha)

- Shaddantajataka (A jataka Tale)

as my favourite panels.

Ajanta... 

In early March, when we visited Ajanta, I was eagerly waiting to see these 2 depictions there - in 2D - as paintings.

To my surprise there was an additional tale there(Matriposhaka Jataka), with an elephant as its central character.

Although all the 3 paintings are quite damaged, with the help of earlier photographs and line drawings - we can appreciate both the similarity and subtle differences in the depiction of 'the Elephant and its kin and kith' between these 3 paintings.

Apart from the above, Elephants are also portrayed frequently in many other panels - leading a royal procession, part of a marching retinue going for a war, part of a jungle scene or as a stand alone emblem/motif in the Ceilings/ Pillars.

Depictions of Elephant(s) in Ajanta  

After coming back, I revisited the Museum, and was struck both by the

- Similarity in the depictions

- Variations obviously due to the difference in media and scale.

Subjugation of Nalagiri 

In this tale, Devadutta, a cousin of Buddha wants to seize power of the monastic order and conspires with King Ajatashatru, to kill Buddha. They decide to release a wild elephant named Dhanapala / Nalagiri. 

Accordingly when Buddha comes begging for alms, in the main street of Rajagriha, Nalagiri is let out of his stable. The elephant charges into the street, destroying and stamping over all in its path. However when he sees Buddha, he is tamed by Buddha's power of benevolence and bows down on his knees before him.

In Ajanta, this highly damaged panel, is located in the Verandah of Cave 17, on the right side, largely above the Lintel. It can be divided into 5 scenes. 

1. Devadutta conspiring with Ajathashatru in his palace.

2. People waiting for Buddha to arrive.

3. Nalagiri released from the stable.

4. Charging down the street.

5. Nalagiri subjugated.

Nalagiri - Cave 17 Verandah - Schlingloff

Scenes 4 and 5 from the Panel

Nalagiri is portrayed essentially only in Scenes 3,4 and 5. Out of these Scene 3 is largely destroyed.

In the scenes 4 and 5 we can see the Majestic elephant in all its grace and strength - dynamically portrayed, 

- First as it charges in the street - personification of power and destruction and

- Later as it bows in front of Buddha, it is portrayed in all its benevolence and submission - seeking Buddhas grace and acceptance.

The beautiful market scene at the back, helps to capture these 2 moods.

- In the first scene people are scared and horrified with shop keepers hurriedly closing their shutters.

- In the 2nd scene, people are awed by Buddhas power and grace, and ladies are cheering and throwing their ornaments as offering.

Scene 4 - Charging of the Rogue Elephant

Scene 5 - Nalagiri's submission and surrender to Buddha   

The scale of Buddha, towering over the entire frame and Nalagiri, and his posture of benevolence, kindness and blessing, complementing the majestic elephant bowing on its all 4s is the beauty of this composition. 

The frenzy of activity in the background also contrasts with the minimalistic foreground, highlighting the focus.

Typical of Ajanta art, Architectural elements have been used, effectively, to delineate the individual scenes and connect them into a coherent composition. Some of these are

-  The 2 storeyed building in Scene 1 depicting 2 scenes of simultaneous action

-  Pavilion in Scene 2 to create focus

-  Gates on either side of Scene 3 - acting as transition and depicting the movement of Nalagiri as he is charging

-  The series of buildings at the back, in Scenes 4 and 5, creating the space and milieu of the street and helping to create the moods of the people from shock, horror to amazement and happiness at last.

Amaravathi - Nalagiri Panel

This panel is hardly 75cms in diameter and carved in Limestone with a polished finish. 

The story is concise and the 2 important scenes depicted are

- Nalagiri charging and destroying

- Nalagiri subjugated.

The similarities with the depiction in Ajanta (inspite of the variations in scale, size, medium and time period) is amazing.

-  Emphasizing on the focal scenes with a dynamic central Nalagiri.

-  The 2 contrasting poses of Nalagiri (portrayed even better here).

-  Scale of Buddha dominating over Nalagiri and the people.

-  Contrasting moods of completely detailed people portrayed on the street and balconies of buildings.

-  Use of Architectural elements to depict a space, a scene, movement and transition and the moods of people.

The differences or contrasts, as already mentioned, arise out of the limitations of size and medium.

-  Concise and abridged depiction with no preliminaries.

-  Fewer people and buildings.

Yet the fluidity of motion and passage and the completeness of the story is retained, making this an absolute masterpiece!

The 2 poses of Nalagiri and the scale vs Buddha

Architectural Elements used to identify space, transition and create moods.

While googling I came across, several more depictions of Nalagiri, alas, none of which have I seen in person.

A Panel from Goli in Chennai Museum (not on display)

Amaravati Panel from British Museum

Gandhara Art - Location Unknown

2nd century, Khyber Pakhtunkhwa, Pakistan, Central Archaeological Museum in Lahore
3rd century, Pakistan (Gandhara Culture), Kushan Period, Indian Museum, Kolkata.

2nd-3rd century, Gandhara, Private collection, Indian and Southeast Asian, Christie’s.
3rd-4th century, Gandhara, private collection
4th century, Northwest Frontier, Peshawar, Pakistan, Government Museum.

Undated, Gandhara, Indian Museum in Kolkata (India).
5th century, Khyber Pakhtunkhwa, Pakistan, Central Archaeological Museum, Lahore (Pakistan). 

Preah Palilay, Angkor, Cambodia (on the Northern Gopuram)

From all these depictions, we can clearly see the variations and variety in Buddhist Art through the Centuries and through the styles of Ajanta, Gandhara and Amaravathi.

Yet we can also observe and appreciate the similarities in these depictions

- In their Narrative Format

- Focus on the Primary Scene (Climax of the Story)

- Sense of Scale - Buddha is uniformly larger than Nalagiri

- The quality of Movement, Fluidity and Dynamism within the Panel even though Buddha himself is static (He is not performing like the Hindu sculptures where the God is fighting, dancing, slaying etc).

- People who form part of the scene are completely detailed out including their varied phyiscal actions and expressions.

- Architectural Elements, acting as Integral components, highlighting the sense of identity, space, scale and as backdrops to the focal scene. 

This is a true revelation to me and appears unique only to Buddhist Art.

No other form of Indian Art or Western Art seems to have borrowed any of these key elements.

Modern Depictions of Taming of Nalagiri

Yet our Modern depictions, either through ignorance or willful thwarting of style, seem to have completely lost both the sense of scale and the true narrative idiom of the Ancient Buddhist Art and come across only as cheap imitations at best, completely lacking the fluidity and richness of style present in the old Art.

They show no context or identity in the detailing of their people, and architectural elements are non existent. Infact Buddha seems to be taming Nalagiri in some scenic tourist spot, rather than a crowded Market place.

I wonder, if this is how our Art becomes more and more mediocre & root less

- in cutting off its ties with Ancient traditions

- yet not able to establish a relevant modern context or identity leaving it in a limbo of vacuum, showing no evolution or continuum, with our past.