Summary of scientific contributions
Professor M. Vijayan has made original and novel contributions pertaining to the structure and carbohydrate binding properties of lectins; the role of hydration in the mobility and action of proteins; structural biology of mycobacterial proteins; and molecular recognition and aggregation of amino acids and peptides, and their probable evolutionary implications.
Prof. Vijayan and his colleagues have dealt with four of the five structural classes of plant lectins. They have studied in detail lectins from peanut, winged bean (basic and acidic), jackfruit (jacalin and artocarpin), garlic, banana and snake gourd. They 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 b-prism I fold. They established b-prism I fold as a lectin fold. They elucidated the roles of water-bridges, post-translational modification, oligomerisation and variation in loop length as strategies for generating ligand specificity. Their studies provided valuable insights into the structural basis of carbohydrate specificity and the biological implications of this specificity. Currently, they are involved in extending the work to lectins from mycobacteria. They have also identified and characterized lectins from archaea.
Using an approach involving water-mediated transformations Professor Vijayan's group has elucidated the nature of the flexibility in lysozyme and ribonuclease A and identified the invariant features in their hydration shells. They have also demonstrated the presence of ensembles of relaxed and tense states of hemoglobin and water-mediated loop movement in b-lactoglobulin. More interestingly, these studies have provided insights into the relationship among hydration, molecular mobility and protein action.
Prof. Vijayan orchestrated a national programme on the structural biology of microbial pathogens. His own personal research in the area has been concerned with mycobacterial, particularly TB, proteins. The specific systems studied by him include RecA, single stranded DNA binding protein, ribosome recycling factor, pantothenate kinase, peptidyl tRNA hydrolase, uracil DNA glycosylase, MutT proteins 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.
Furthermore, Professor Vijayan and his colleagues have elucidated, using a novel approach based on molecular complexes, molecular recognition and aggregation patterns involving amino acids and peptides, which have been shown to have implications to chemical evolution and origins of life Their 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.
addition, Professor Vijayan has played a leading role in the development of
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