β-pleated sheet

Definition

A β-pleated sheet is a common secondary structure in proteins characterized by two or more polypeptide chains lying side by side, linked together by hydrogen bonds. This structure forms a sheet-like arrangement that can be parallel or antiparallel.

5 Must Know Facts For Your Next Test

1. β-pleated sheets are stabilized by hydrogen bonds between the carbonyl oxygen of one amino acid and the amide hydrogen of another.
2. They can be found in both parallel and antiparallel orientations depending on the direction of the polypeptide chains.
3. β-pleated sheets contribute to the overall stability and rigidity of protein structures.
4. They play a crucial role in the structural framework of many proteins, including silk fibroin and amyloid fibrils.
5. Misfolded β-pleated sheets are associated with several diseases, such as Alzheimer's disease and prion diseases.

Review Questions

• What type of bonding stabilizes β-pleated sheets?
• How do parallel and antiparallel β-pleated sheets differ?
• Name one disease associated with misfolded β-pleated sheets.

Related terms

Alpha helix: A common secondary structure in proteins characterized by a coiled shape held together by hydrogen bonds.

Hydrogen bond: A weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other.

Protein folding: The process by which a protein assumes its functional three-dimensional shape.