Question

Classify each peptide chain as part of a parallel β sheet, part of an antiparallel β sheet, either type of β sheet, or not part of a β sheet.

1) Part of a parallel β sheet
2) Part of an antiparallel β sheet
3) Either type of β sheet
4) Not part of a β sheet

Answer 1

There are two types of β sheets formed by polypeptide chains: parallel and antiparallel. A parallel β sheet has neighboring chains with N-termini on the same side, while an antiparallel β sheet has N-termini on opposite sides. If the type cannot be determined, it is classified as either type of β sheet.

Step-by-step explanation:

The parallel β sheet and antiparallel β sheet are two types of β sheets formed by polypeptide chains in proteins.

1. Parallel β sheet: In this type, the N-terminus of neighboring chains is on the same side. This creates a pleated shape with multiple parallel chains running in the same direction.
2. Antiparallel β sheet: In this type, the N-terminus of neighboring chains is on opposite sides. This results in a pleated shape with chains running in opposite directions.
3. Either type of β sheet: This refers to a situation where the type of β sheet cannot be determined from the provided information.
4. Not part of a β sheet: This refers to a peptide chain that does not form a β sheet structure.