G.N. Ramachandran

Dr. Gopalasamudram Narayana Ramachandran (1922–2001) was an eminent Indian physicist and molecular biophysicist who made pioneering contributions to the understanding of protein structure and molecular conformation. He is best known for creating the Ramachandran Plot, a fundamental tool in structural biology that maps the allowed conformations of amino acid residues in protein structures. His groundbreaking research bridged physics, chemistry, and biology, establishing India’s global reputation in molecular biophysics.

Early Life and Education

G. N. Ramachandran was born on 8 October 1922 in Ernakulam, Kerala, into a scholarly Tamil Brahmin family. His father, G. R. Narayana Iyer, was a professor of mathematics at Maharaja’s College, Cochin, and his mother, Lakshmi Ammal, encouraged his intellectual pursuits.
Ramachandran’s early education took place at Ernakulam Government School, followed by St. Thomas College, Thrissur. His exceptional aptitude for science and mathematics earned him a B.Sc. (Honours) in Physics from St. Joseph’s College, Trichy, affiliated with the University of Madras, in 1942.
He went on to complete his M.Sc. in Physics at the Indian Institute of Science (IISc), Bangalore, under the guidance of Sir C. V. Raman, the Nobel laureate who discovered the Raman Effect. His master’s dissertation on X-ray diffraction of crystals marked the beginning of his lifelong interest in structural physics.
In 1947, Ramachandran travelled to England to pursue doctoral research at Cambridge University, working with Sir Lawrence Bragg, the co-discoverer of X-ray crystallography. He earned his Ph.D. in Physics in 1949 for his research on the determination of crystal structures using Fourier methods.

Academic and Research Career

After completing his doctorate, Ramachandran returned to India and joined the Department of Physics at the University of Madras, where he established the Department of Physics and Crystallography Laboratory in 1952. This department became one of the earliest centres of molecular biophysics in the world.
In 1970, he moved to the Indian Institute of Science (IISc), Bangalore, where he founded the Molecular Biophysics Unit (MBU), which remains a premier research institute in structural biology today.
Ramachandran served in various academic and research capacities, mentoring numerous scientists who later became leaders in Indian science.

The Ramachandran Plot and the Structure of Proteins

Ramachandran’s most celebrated contribution came in the early 1950s when he, along with his student V. Sasisekharan, formulated the Ramachandran Plot (1963). This diagram mapped the sterically allowed conformations of the peptide backbone in proteins by plotting the torsion angles — phi (φ) and psi (ψ) — around the alpha carbon atom of amino acids.
The Ramachandran Plot revealed that only certain combinations of these angles are physically possible due to steric hindrance (the repulsion between atoms that prevents overlap). This insight became a cornerstone of structural biology, providing the first theoretical explanation for the geometry of protein folding.
Key implications of the Ramachandran Plot include:

• Validation of experimentally determined protein structures obtained from X-ray crystallography and NMR spectroscopy.
• Identification of common structural motifs such as alpha helices, beta sheets, and turns in proteins.
• Establishing the geometric and energetic basis of peptide conformation.
• Providing a universal tool for computational modelling and structural refinement.

To this day, the Ramachandran Plot remains a fundamental part of every biochemistry and structural biology curriculum worldwide.

Discovery of the Triple Helix Structure of Collagen

Another of Ramachandran’s major achievements was the proposal of the triple helical structure of collagen in 1954, independently and simultaneously with scientists Francis Crick and Alexander Rich.
Using X-ray diffraction data, Ramachandran demonstrated that collagen — the most abundant protein in mammals — is composed of three polypeptide chains wound around each other in a triple helix. His model, known as the Ramachandran–Kartha model (developed with Gopinath Kartha), correctly explained the fibre diffraction pattern and provided the first accurate understanding of collagen’s molecular architecture.
This discovery represented a significant milestone in molecular biology, second only to the discovery of the DNA double helix. It established Ramachandran as one of the leading structural biologists of his time.

Advances in Crystallography and Molecular Biophysics

Ramachandran’s research extended beyond proteins to include several aspects of crystallography and biophysics. He developed innovative methods for analysing molecular structure and diffraction patterns, including:

• Fourier synthesis and refinement techniques for determining atomic positions.
• Mathematical models of interatomic distances and bond angles in macromolecules.
• Studies on biopolymer conformation and electron density distribution.

He also introduced concepts of stereochemical restraints and non-bonded interactions, which are now standard in computational structural biology.

Founding of Institutions and Academic Leadership

Ramachandran’s influence went beyond research; he was instrumental in building India’s infrastructure for molecular science.
At the University of Madras, he established one of the earliest interdisciplinary biophysics programmes, combining physics, chemistry, and biology. Later, at IISc Bangalore, he founded the Molecular Biophysics Unit (MBU) in 1970, which became a model for interdisciplinary scientific research in India.
He also served as an advisor to the Council of Scientific and Industrial Research (CSIR) and contributed to national policies on scientific research and education.

Awards and Honours

Dr. G. N. Ramachandran received numerous national and international honours for his outstanding scientific contributions, including:

• Shanti Swarup Bhatnagar Prize for Physical Sciences (1958).
• Fellow of the Royal Society (FRS) (1977), one of the highest honours for a scientist.
• Padma Bhushan, India’s third-highest civilian award (1963).
• Elected Fellow of the Indian Academy of Sciences, Indian National Science Academy, and several international scientific bodies.
• Honorary doctorates from multiple universities for his exceptional contributions to molecular science.

Personality and Teaching Style

Ramachandran was known for his precision, intellectual rigour, and innovative thinking. A deeply curious and disciplined scientist, he combined theoretical understanding with experimental intuition.
As a teacher, he was inspiring yet demanding, encouraging his students to think independently and rigorously. His lectures were known for their clarity and depth, often integrating physics and mathematics to explain biological phenomena.
Outside the laboratory, he was an accomplished artist and philosopher, known for his interest in the interface between science and spirituality.

Later Life and Challenges

In his later years, Ramachandran suffered from Parkinson’s disease, which limited his physical mobility but not his intellectual vitality. Despite his illness, he continued to guide research and publish scientific papers.
He retired in 1983 but remained scientifically active until his health declined. He passed away on 7 April 2001 in Chennai, leaving behind an enduring scientific legacy.

Legacy and Scientific Impact

The influence of G. N. Ramachandran’s work continues to be profound and far-reaching. The Ramachandran Plot remains a universal standard for validating protein structures in crystallography and bioinformatics. His studies on collagen structure and molecular geometry shaped the development of structural biology as a discipline.
In recognition of his lifelong contributions:

• The G. N. Ramachandran Memorial Lecture Award was instituted by the Council of Scientific and Industrial Research (CSIR).
• The Indian Academy of Sciences honours him annually through lectures and awards in biophysics.
• His name is permanently enshrined in textbooks, scientific literature, and molecular visualisation software used globally.