ABSTRACT
Proteins are biological macromolecules and are present in and vital to all living organisms.
ey carry out a wide variety of functions-catalyze a range of reactions in the cell, provide structural rigidity to the cell, control transport across the cell membrane, act as sensors and switches in cell signaling, cause motion, bind to foreign bodies in immune response, and control gene function. Structurally, proteins are heteropolymers of the 20 naturally occurring α-amino acids. e amino acids can have varied chemical characters-apolar, polar, acidic, or basic-depending on the identity of the side chain group attached to the α-carbon. e amino acids are connected to each other through the peptide bond and the sequence in which the amino acids are connected is known as the primary structure of the protein. Proteins adopt a well-dened 3D structure, also called the tertiary or native structure, in solution. is usually consists of secondary structures-locally organized structural elements such as α-helices, β-sheets, turns-held together by noncovalent interactions and, in some cases, by disulde bonds. Proteins in solution are not static entities-rather they undergo conformational uctuations and transitions. It has been realized that the diverse array of functions carried out by proteins is intimately connected to its structure and dynamics.
