Biochemistry—β-Pleated Sheet Details In β-pleated sheet structures, which statement is accurate about how neighboring strands relate?

Introduction / Context:β-Sheets are stabilized primarily by hydrogen bonds between backbone atoms of adjacent strands. This question distinguishes correct inter-strand bonding from incorrect ideas about intra-strand bonding and obligatory helical connectors.

Given Data / Assumptions:

• β-Sheets consist of multiple strands arranged side by side.
• Backbone C=O and N-H groups form inter-strand hydrogen bonds.
• Connections between strands (loops/turns) vary and are not always α-helices.

Concept / Approach:Identify which statement captures the defining stabilizing interaction. Inter-strand hydrogen bonding is the core principle; intra-strand adjacent residues typically do not hydrogen bond in β-conformation.

Step-by-Step Solution:

Verification / Alternative check:Inspection of β-sheet cartoons and PDB structures confirms inter-strand hydrogen bonding as the stabilizing network, with variable types of connecting segments.

Why Other Options Are Wrong:

• Neighboring residues along the same strand: not the primary H-bonding pattern in β-strands.
• Connected by α-helices: not a rule; often short turns/loops connect strands.
• Avoid hydrogen bonds: opposite of reality—hydrogen bonds stabilize sheets.
• “Planar sheet” alone is descriptive but incomplete; hydrogen bonding is the key correct feature.

Common Pitfalls:Assuming all secondary elements are linked by helices; confusing inter-strand with intra-strand bonding; overlooking that sheets are pleated, not perfectly flat.

Final Answer:Neighboring chains are hydrogen bonded to each other through backbone groups.