BLG 888 Lecture Notes - Lecture 4: Alpha Helix, Covalent Bond, Sickle-Cell Disease
16 Jan 2017
School
Department
Course
Professor
Document Summary
R-group orientation- side chains can interact with each other or h2o. Heteromultimeric protein- different chains levels of protein structure: Secondary structure: a-helix is right handed, stabilized by h-bonds each peptide carbonyl is h bonded to the peptide n-h group 4 residues farther up the chain helix breakers: proline, glycine, serine, threonine. Proline has a fixed angle, glycine is too flexible, serine and threonine have hyrolxyl groups that participate in hydrogen bonding- will destabilize alpha helix arginine is equally found in a-helix, b-sheets, and b-turn polyaminoacids: polyleucine, polyalanine. B-pleated sheets: -sheets are held in place by hydrogen bonds between peptide bonds adjacent in space but that may be distantly located in the primary structure side chains alternate pointing up and down r-handed twist viewed along strands. Antiparallel is stronger than parallel due to hydrogen bonding- more stable and linear. One bump is 7 angstroms long can be cylindrical or barrel shape parallel sheets: typically large structures.
