Which one of the following is INCORRECT about protein structures?

Q. Which one of the following is INCORRECT about protein structures?

(A) A protein fold is stabilized by favorable non-covalent interactions

(B) All parts of a fold can be classified as helices, strands or turns

(C) Two non-covalent atoms cannot be closer than the sum of their van der Waals radii

(D) The peptide bond is nearly planar

Ans: All parts of a fold can be classified as helices, strands or turns