Molecular dynamics simulation studies of interfacial activation and thermostability of enzymes

Abstract

Proteins are one of the four essential components (nucleic acids, proteins, carbohydrates and lipids) of all living systems. They perform a wide spectrum of functions ranging from catalysis, signal transduction, maintaining electrochemical potentials in intra- and extra-cellular regions through the transport of molecules and ions across cell membranes, and providing rigidity to cells and tissues. Proteins are polymers of amino acids which are covalently linked to each other to form a polypeptide chain [1]. The sequence of amino acids across the polymer chain forms the primary structure of a protein. This sequence, to a good extent, determines the structure of the protein [2]. The folding of long polypeptide chain give rise to different kinds of local structures, called the secondary structure of a protein. -helix and -sheet are the two most prominent structural elements among several secondary structures of proteins. These two structural elements connect through other secondary structural motifs (small 3/10-helices, random coils, etc.) to produce an overall proper fold termed as the tertiary structure of a protein [3]. The association of more than one tertiary structural units may result in a quaternary structure. A quaternary structure can be an assembly of either homomeric subunits or heteromeric subunits [1, 3]. A well-known example of a quaternary structure is haemoglobin consisting of two 2 2-units of myoglobins.