V. Sasisekharan

Viswanathan Sasisekharan (born 1933) is an Indian biophysicist known for his work on the structure and conformation of biopolymers. He introduced the use of torsion angles to describe polypeptide and protein conformation, a central principle of the (φ, ψ) plot (later known as the Ramachandran plot). Additionally, he was the first to introduce alternative models of DNA structure that provided insights beyond the standard double helix model. For his contributions to the biological sciences, he was awarded the Shanti Swarup Bhatnagar Prize for Science and Technology, one of India’s highest science awards, in 1978.

Education and career V. Sasisekharan was born on 28 June 1933 in the South Indian state of Tamil Nadu. He earned his Ph.D. from the University of Madras in 1959. From 1959–1963, he was a lecturer at the University of Madras, and from 1963–1964, he was a visiting scientist at the National Institutes of Health (NIDDK).

Research As a graduate student, Sasisekharan studied the structure of collagen chains and developed methods to generate the coordinates of constituent atoms of peptides with a high degree of accuracy. Using this approach and published crystal structures, he identified allowable non-bonded distances between atoms of consecutive amino acids. While Sasisekharan calculated these allowable regions using only a few available protein crystal structures at the time, the (φ, ψ) plot has remained nearly unchanged for 60 years.

His son, Ram Sasisekharan, is a bioengineer and a co-author of some of his publications.

Awards and honors The Council of Scientific and Industrial Research awarded Sasisekharan the Shanti Swarup Bhatnagar Prize (one of India’s highest science awards) in 1978 for his contributions to the fields of biopolymers and DNA structure analysis. In 1985, he held the ASTRA chair in Biological Sciences at the Indian Institute of Science and received the Jagdish Chandra Bose Award for Research in Life Sciences from the University Grants Commission of India. Sasisekharan was elected fellow of the Indian Academy of Sciences in 1969 and fellow of the Indian National Science Academy in 1980.