Chapter 6 - Secondary Structure of Proteins

Abstract

The chapter begins by explaining the secondary structure of proteins. The overall conformation of the main chain of a protein is determined by three torsional bond angles, one of which is fixed by chemical bonding rules. Therefore, the definition of three torsional bond angles for each amino acid in a polypeptide chain is sufficient to describe the entire conformation of the main chain of a protein. If these torsional angles have repeating values for a set of contiguous amino acids, the polypeptide segment has secondary structure. The most common forms of secondary structure: the α helix and β strands. The chapter first explains the reasons for analyses in terms of the secondary structure and then; details the chemical nature of a polypeptide chain. The chapter further provides definitions for secondary structure. The β helix is then discussed, and turns assigned to segments of proteins are also detailed. The chapter then provides information on the collagen triple helix, and concludes with a discussion on predictions of the secondary structure.