4. Protein Structure

A Ramachandran plot shows:

Why are some regions of a Ramachandran plot shaded while others are unshaded? Circle all true answers.

The predominate structure in α-keratin, a mammalian protein that makes up large portions of hair & nails, is the α-helix. Mark the approximate locations on a Ramachandran plot you might expect to find φ and ψ angles for α-keratin amino acid residues.

The principal component of silk is the protein fibroin, which is a classic example of β-sheet structure. Mark the approximate locations on a Ramachandran plot you might expect to find φ and ψ angles for silk amino acid residues.

Which of the following statements is true for the portion of the peptide shown in the figure below?