Which of the Following Factors is NOT Considered a Level

Question

Which of the following factors is NOT considered a level of protein structure?
A)the interaction between subunits of a protein
B)the order of amino acid residues in the peptide chain
C)the 3-dimensional arrangement of all atoms in a single peptide
D)the hydrogen bond arrangement of nonpolar R-groups

Accepted Answer

The hydrogen bond arrangement of nonpolar R-groups is not considered a level of protein structure. The four levels of protein structure are primary (order of amino acid sequence), secondary (local folding patterns such as alpha helices and beta sheets), tertiary (overall 3D folding of a single polypeptide chain), and quaternary (interactions between multiple polypeptide chains in a protein complex). The interaction between subunits is a part of quaternary structure, and the 3D arrangement of atoms in a single peptide is part of tertiary structure.