You are studying the characteristics of protein secondary structure. You find that the protein you are examining forms an α-helical structure more rapidly in an alcohol medium than it does in water. Which of the following is the best explanation for this difference?
A) competition for hydrogen bonding is lower for ethanol than for water
B) ethanol forms covalent interactions with the peptide
C) hydrophobic forces are greater in ethanol than in water
D) the peptide aggregates in water but not in ethanol
E) van der Waals interactions are lower in ethanol than in water

Question

Quizplus · Accepted Answer

Alcohols like ethanol have lower hydrogen bonding competition compared to water, allowing the protein to form α-helices more readily. The α-helix results due to the formation of hydrogen bonds between adjacent amino acids in the protein. Because these same atoms in the amino acids can form hydrogen bonds with water, there can be competition for the formation of the bonds required for the α-helix. In the presence of ethanol there would be less competition from the water molecules thus explaining the increased rate of α-helix formation in this medium.

You Are Studying the Characteristics of Protein Secondary Structure