ST Turn

Motif Glossary

ST Turn

Definition

A motif of three consecutive residues and one H-bond in which there is:

• Serine or Threonine (ST) at residue-1
• H-Bond between side-chain O of residue-1 and main-chain NH of residue-3.

Sub-categories

These encompass the following conformations for each of Ser and Thr:

• 1,2-χ60αR (aka: type I or R-handed)
• 1,2-χ60αL (aka: type II or R-handed flipped)
• 1,2-χ180αL (aka: type I' or L-handed)
• 1,2-χ180αR (aka: type II' or L-handed flipped)

Reference

Duddy and Milner-White, Protein Sci. 13:3051-3055 (2004)

Comments

1. The ST Turn, like the Asx Turn, resembles the H-bonded Beta Turn in the sense that side-chain atoms of residue-1 mimic the main-chain of residue-1 of Beta Turns.

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