BIOC 2580 Lecture Notes - Lecture 6: Bond Length, Hydrogen Bond, Globular Protein
8 Dec 2017
School
Department
Course
Professor
Document Summary
Synopsis: the polypeptide backbone flexes by rotation about its single bonds. Two arrangements result in regular repetitive structure, helix and sheet. Amino acid can be grouped in three classes: amino acids with bulky side chains prefer to form sheet; a second group of amino acids have side chains that disrupt secondary structure; the remaining amino acids tend to form helix. The polypeptide chain forms a backbone structure in proteins. On first inspection, this structure appears to be connected entirely by single c c or c n bonds. It should therefore be as flexible as a simple hydrocarbon chain. Flexing in a covalent chain structure does not occur by bending bonds, and can be achieved while the normal tetrahedral or trigonal planar bond angles are maintained. Instead, different shapes are obtained by rotation about the axis of single bonds. A chain made only of single bonds is highly flexible.
