ST staple
The ST staple is a common four- or five-
carbonyl group of residue i. Motifs are of two types, depending whether the motif has 4 or 5 residues. Most ST staples occur in conjunction with an alpha helix, and are usually associated with a slight bend in the helix. Two websites are available for finding and examining ST staples in proteins: Motivated Proteins[3] and PDBeMotif.[4]