ST Staple

Motif Glossary

ST Staple

Definition

A motif of four or five consecutive residues and one H-bond in which there is:

• Serine or Threonine (ST) at the final residue (-4 or -5)
• H-bond between the side-chain OH of the final residue and the main-chain CO of residue-1
• αR conformation at the residues not involved in H-bonding (-2, -3, and, for the 5-residue variant, -4).

Sub-categories

There are sub-categories to distinguish between Ser and Thr for each of the 4-residue and 5-residue variants.

Reference

Milner-White, unpublished

Comments

1. The current definition differs slightly from that used previously, in that it explicitly restricts the inner residues to the αR conformation, excluding any in the βR conformation.

2. The Ser or Thr side-chain can be regarded as stapling together two adjacent turns of α-helix.

3. Because of the stipulation for an αR conformation in the loop residues, 5-residue ST Staples will almost invariably also have a main-chain H-bond between the NH of residue-5 and the CO of residue-1 (see 3D view).

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