BCH 2333 Lecture Notes - Lecture 6: Dihedral Angle, Entropy, Glutamine
16 Dec 2017
School
Department
Course
Professor
Document Summary
Primary structure: order of amino acids (from n terminus to c terminus) Secondary structure: small localized areas of structural units. Tertiary structure: interaction of secondary structures to form a larger structure. Quaternary structure: at least 2 tertiary structures join together. Native fold: proteins adopt a speci c 3d conformation. Has a large number of favourable interactions within the protein. Needs to be favourable because adopting only one conformation has a very strong entropic penalty. Entropic cost must be overcome by favourable interactions in order for proteins to fold. Shorter than c-n single bond (0. 13 shorter), c=o bond is slightly longer than usual (0. 02 longer) Partial double-bond character (40%): resonance form has double bond. Amide is in the same plane (amino + carbonyl) Most peptide groups adopt the trans con guration (looking at the carbonyl and the h of the nh) Dihedral angle (omega - ): looking down peptide bond axis.
