Beta-Turn
Beta-Turn — A secondary structural element where the peptide chain reverses direction by approximately 180 degrees over four residues.
What Is a Beta-Turn?
A beta-turn (reverse turn, beta-bend) is a structural motif in which the peptide backbone reverses direction over four residues, with a hydrogen bond between the CO of residue i and the NH of residue i+3. Beta-turns connect adjacent strands of beta-sheets and are the second most common secondary structure element after helices.
Turn Types and Peptide Design
- Type I: Most common. Pro favored at i+1 position
- Type II: Gly required at i+2 due to positive phi angle
- Type I'/II': Mirror-image turns. D-amino acids stabilize these conformations
- Design tool: D-Pro-Gly is a powerful turn-inducing dipeptide used in cyclic peptide design
Frequently Asked Questions
What is Beta-Turn?
A secondary structural element where the peptide chain reverses direction by approximately 180 degrees over four residues.
Why is Beta-Turn important in peptide research?
Beta-Turn is a fundamental concept in structure as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.