Beta Turn

Motif Glossary

Beta Turn

Definition

A motif of four consecutive residues and one H-bond in which:

• H-bond occurs between main-chain CO of residue-1 and main-chain NH of residue-4
• Residues do not form part of an α-helix or a 3-10 helix.

Sub-categories

• 2,3-αRαR (aka: type I or R-handed)
• 2,3-βRαL (aka: type II or R-handed flipped)
• 2,3-αLαL (aka: type I' or L-handed)
• 2,3-βLαR (aka: type II' or L-handed flipped)

Reference

Venkatachalam, Biopolymers 6:1425–1436 (1968)

Comments

A broader definition of Beta Turn which does not require the H-bond may be found in the literature.

Occurrence

Beta turns are typically found connecting anti-parallel strands of a β-sheet.

Introduction AlphaBeta Loop Asx Motif Asx Turn Beta Bulge Beta Bulge Loop Beta Link Beta Turn BulgeLoop Motif Crown Bridge Crown Bridge Loop Nest Niche Schellman Loop ST Loop ST Motif ST Staple ST Turn