BSCI-2520 Chapter 6: Chapter 6
Document Summary
The peptide bond has some double bond character because of resonance. This causes the surrounding group (peptide group) to be rigid. Some pro residues have cis bonds (less steric hindrance). Definition: angle described by the bonds between four successive atoms. Indicates the sterically allowed conformations of a polypeptide. Blue: sterically allowed for all residues except gly and pro. Pro = most sterically restricted because of its ring. Gly = most sterically free because side chain is only an h. Both have regularly repeating structures (are called regular secondary structures) Has a favorable h-bond pattern (nearly optimum distance) Very tightly packed core (van der waals contact) Connection between two strands may be a small loop or more complex. Can be in the plane of the strands. Neighboring h-bonded chains run in the same direction. Connection between two stands is always a crossover connection outside of the plane of the stands.