The major reason that antiparallel β-sheets are more stable than parallel β-sheets is that the latter:

• A. Are in a slightly less extended configuration than antiparallel strands.
• B. Do not have as many disulfide crosslinks between adjacent strands.
• C. Do not stack in sheets as well as antiparallel strands.
• D. Have fewer lateral hydrogen bonds than antiparallel strands.
• E. Have weaker hydrogen bonds laterally between adjacent strands.

Answer: (E)

Verified step by step guidance

1. Understand the structure of β-sheets: β-sheets are a type of secondary structure in proteins, consisting of β-strands connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet.
2. Differentiate between antiparallel and parallel β-sheets: In antiparallel β-sheets, the N-terminus to C-terminus direction of adjacent strands is opposite, while in parallel β-sheets, the strands run in the same direction.
3. Analyze hydrogen bonding in β-sheets: In antiparallel β-sheets, the hydrogen bonds between the strands are more linear and thus stronger, compared to the less linear and weaker hydrogen bonds in parallel β-sheets.
4. Consider the impact of hydrogen bond strength on stability: Stronger hydrogen bonds in antiparallel β-sheets contribute to greater stability compared to the weaker hydrogen bonds in parallel β-sheets.
5. Conclude why antiparallel β-sheets are more stable: The key reason for the increased stability of antiparallel β-sheets is the stronger, more linear hydrogen bonds between adjacent strands, making them more stable than parallel β-sheets.