Past Event: Oden Institute Seminar

How salt modulates protein-protein interaction from repulsive to attractive: A computational study of B-lactoglobulin dimer formation

Pradipta Bandyopadhyay, Computational and Integrative Sciences, Jawaharlal Nehru University

Abstract

Electrostatics is one of the major interactions in molecular systems. One intriguing phenomenon in electrostatics is that two large molecules, having the same sign of charges, can attract each other in the presence of counterion and/or salt. In this work, we have investigated the salt-dependent attraction between the monomers of a protein, B-lactoglobulin, in spite of carrying a large net charge. The calculation of binding free energy of salt-dependent protein-protein interaction is challenging as it involves subtle changes in the electrostatic interaction. We have used a combination of molecular dynamics simulation and reference interaction site model (RISM) to calculate binding free energy between protein monomers at different salt concentrations, which matches the experimental results semi-quantitatively. An explanation of how salt modulates the electrostatic interaction between the protein monomers will be given.