Vijayan's students and postdocs have dealt with four of the five structural classes of plant lectins. They have studied in detail lectins from peanut, winged bean, jackfruit, garlic, banana and snake gourd. The work on lectins demonstrated the need for considering open quaternary structures when dealing with multimeric proteins and the variability in the quaternary association of legume lectins. and lectins with the β-prism I fold. His group established β-prism I fold as a lectin fold. They explained the roles of water-bridges, post-translational modification, oligomerisation and variation in loop length as strategies for generating ligand specificity. Their studies provided insights into the structural basis of carbohydrate specificity and the biological implications of this specificity. Using an approach involving water-mediated transformations, Vijayan's research determined the nature of the flexibility in lysozyme and ribonuclease A and identified the invariant features in their hydration shells. His research also demonstrated the presence of ensembles of relaxed and tense states of haemoglobin. and water-mediated loop movement in β-lactoglobulin. His studies have provided insights into the relationship among hydration, molecular mobility and protein action. Vijayan organised a national programme on the structural biology of microbial pathogens. His research in the area has been concerned with mycobacterial, particularly tuberculosis, related proteins. The specific systems studied by him include RecA, RuvA, uracil DNA glycosylase, single stranded DNA binding protein, ribosome recycling factor, peptidyl tRNA hydrolase, pantothenate kinase and DNA binding protein in stationary phase cells. He has elucidated the specific structural features of these proteins in mycobacteria, which, among other things, have opened up avenues for structure-based inhibitor design, with the eventual objective of drug development. Vijayan's research have determined the molecular recognition and aggregation patterns involving amino acids and peptides using an approach based on molecular complexes. This has implications to chemical evolution and origins of life. His other contributions pertain to the structure and interactions of non-steroidal anti-inflammatory analgesics, ionophores and related compounds, side chain conformation in proteins and additional binding sites in lysozyme. Vijayan has published more than 260 peer reviewed research articles and has guided 38 research students and 20 postdoctoral fellows.
Professional life
After completing his postdoctoral research at the University of Oxford, he returned to India in 1971 and joined the Molecular Biophyiscs Unit at the Indian Institute of Science. He has served in various capacities such as Professor, Chairman of Molecular Biophysics Unit, Chairman of Division of Biological Sciences among others. During 2000–2004 he was Associate Director of IISc. He has continued to work at the Institute as a DBT Distinguished Biotechnologist and subsequently as a DAE Homi Bhabha Professor.
Role in international and national organisations
Vijayan is a member of the International Union of Crystallography, the International Union of Pure & Applied Biophysics, the International Council for Science, the Inter Academy Panel and the InterAcademy Council. He is a former President of the Asian Crystallographic Association. He has been involved in the activities of the science departments and agencies of the Government of India and different scientific institutions in the country. He is the Founder President of the Indian Crystallographic Association and has served as the President of the Indian Biophysical Society and the President of the Indian National Science Academy.
Awards and recognitions
Vijayan is a Fellow of the three science academies of India and the Academy of Sciences for the Developing World. He has won the Shanti Swarup Bhatnagar Prize, GN Ramachandran Medal by INSA, Alumni Award Excell. Res. by IISc, FICCI Award Life Sci., Ranbaxy Res. Award by Basic Medical Sciences, JL Nehru Centen. vis. fellow by INSA, Om Prakash Bhasin Award, KS Krishnan Memorial Lecture by INSA, JL Nehru Birth Centen. Award by Indian Science Congress Assoc., Padma Shri, Distinguished Biotechnologist Award by DBT; Goyal Prize, first CSIR/Science Congress GN Ramachandran Award for Excellence in Biological Science and Technology, Distinguished Alumni Award and Lakshmipat Singhania-IIM Lucknow National Leadership Award for Science and Technology-Leader, 2009.
