For the following phipsi bond combinations state whether the

For the following phi/psi bond combinations, state whether these amino acids are likely to have a particular secondary structure or are in a conformationally-disallowed state due to steric hindrance. phi = 60, psi = 60 phi = -70, psi = 120 phi = 120, psi = -140 phi = -100, psi = -60

Solution

(a) This amino acid will have a secondary structure of left handed alpha helix

(b) This amino acid will also have a secondary structure. Might form a beta sheet conformation.

(c) This amino acid will not form a secondary structure. It falls into the disallowed state due to steric hindrance.

(d) This amino acid will not form a secondary structure. It falls into the disallowed state due to steric hindrance.