Insight derived from molecular dynamics simulation into cold-adaptation mechanisim of trypsins

AbstractIn extremely low temperature environments, psychrophilic proteins must possess enhanced flexibility in order to obtain higher catalytic efficiency. However, the physicochemical basis between psychrophilic proteins’ conformational flexibility and structure stability at low temperatures remain to be understood. Here, we perform comparative molecular dynamics simulations on psychrophilic trypsin (pAST) and its homologous mesophilic trypsin counterpart (mAST), both of which are found in the same species. Through the comparative analyses of dynamic structural and geometrical properties, we discovered that pAST adopted a more relaxed conformation and exhibited less intramolecular interactions and higher global flexibility than mAST, which could result in its favor of higher conformational flexibility at lower temperatures. Comparison between the protein-solvent interactions and the hydrophobicity of these two trypsins revealed that pAST possess a smaller burial of nonpolar area, and more protein-solvent...