Question

Two or three α helices can sometimes wrap around each other to form coiledcoils. The stable wrapping of one helix around another is typically driven by ________________ interactions.

(a) hydrophilic
(b) hydrophobic
(c) van der Waals
(d) ionic

Answer 1

The stable wrapping of one α helix around another in the formation of coiled coils is typically driven by hydrophobic interactions, as nonpolar amino acids in the interior of proteins interact to avoid water.

Step-by-step explanation:

Two or three α helices can sometimes wrap around each other to form coiled coils, a structure stabilized typically through hydrophobic interactions. Hydrophobic interactions occur because the nonpolar amino acid side chains (R groups) tend to aggregate to avoid contact with water, hence favoring the stable interaction between the helices.


This phenomenon aligns with the general principle that nonpolar amino acids lay in the interior of the protein, where they can interact with each other, avoiding the aqueous environment. Other types of interactions such as ionic bonding, hydrogen bonding, disulfide linkages, and dispersion forces (van der Waals forces) also play roles in stabilizing the tertiary structure of a protein.