BCMB20002 Lecture Notes - Lecture 6: Modular Arithmetic, Steric Effects, Covalent Bond

• School: University of Melbourne
• Department: Biochemistry and Molecular Biology
• Course: BCMB20002
• Professor: Terry Mulhern

Document Summary

All figures from lecture 4 and 5 slides of p. gooley, melbourne university, march 2017 (unless stated otherwise) Beta- turns irregular structure: reversing the main chain. Helices and sheets are all regular structures = same phi,psi angles. Two sequential residues with different phi,psi angles: i+1 and i+2. Redirecting the backbone especially on the antiparallel sheets. A hydrogen bond between the carbonyl of the first (i) and the nh of the fourth (i+3), stabilizing the turn. In type 1, the carbonyl of i+1 as facing away from us (into the paper). In type 2, the carbonyl of i+1 and i+2 is both facing towards us, hence occupying the same space (the phi,psi angle is positive here). Most common residue in type 1 is proline. Most common residue in type 2 is glycine as its side chain is only h, so small amounts of steric hindrance.