Question

What is the minimum number of beta-strands that can be twisted and packed to form a beta-barrel structure?

• A. 4
• B. 6
• C. 8
• D. 10

Hint:

Beta-Barrel Minimum = 8 strands (like an Octagon).

Answer 1

The Correct Option is C

Step 1: Concept
A beta-barrel is a large beta-sheet that twists and coils to form a closed structure in which the first strand is hydrogen-bonded to the last.

Step 2: Meaning
These structures are common in porins and other membrane-spanning proteins.

Step 3: Analysis
To create a stable, closed cylinder with a central pore, a minimum of 8 beta-strands is generally required to accommodate the necessary twist and geometry.

Step 4: Conclusion
Eight is the accepted minimum for a functional beta-barrel fold. Final Answer: (C)