title: Correlation of observed fold frequency with the occurrence of local structural motifs.
abstract: It is well known that some protein folds (superfolds) occur very frequently. We show that compared to other folds, most superfold structures have a higher proportion of their alpha-helical or beta-strand residues in one of three basic units of supersecondary structure (alpha-hairpin, beta-hairpin or betaalphabeta-unit). Furthermore, by taking into consideration two more complex motifs, the four-stranded Greek-key (beta4) and the betaalpha-Greek key (betaalphabetabeta), we demonstrate that the remaining superfold structures contain many of these higher order units of three-dimensional packing. The implications of these results for folding are discussed.
authors.affiliation: Biomolecular Structure and Modelling Unit, Department of Biochemistry and Molecular Biology, University College London, London, WC1E 6BT, UK.
authors.forename: G M
authors.initials: GM
authors.lastname: Salem
authors.forename: E G
authors.initials: EG
authors.lastname: Hutchinson
authors.forename: C A
authors.initials: CA
authors.lastname: Orengo
authors.forename: J M
authors.initials: JM
authors.lastname: Thornton
mesh_terms: D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary