The beta bulge: a common small unit of nonrepetitive protein structure.

Journal Article (Journal Article)

A beta bulge is a region between two consecutive beta-type hydrogen bonds which includes two residues (positions 1 and 2) on one strand opposite a single residue (position x) on the other strand. Compared to regular beta structure, a beta bulge puts the usual alternation of side-chain direction out of register on one of the strands, introduces a slight bend in the beta sheet, and locally accentuates the usual right-handed strand twist. Almost all beta bulges are between antiparallel strands, usually between a narrow rather than a wide pair of hydrogen bonds. Ninety-one examples are listed. The two commonest types are the "classic" beta bulge, with position 1 in approximately alpha-helical conformation, and the "G1" beta bulge, with a required glycine at position 1 in approximately left-handed alpha-helical conformation, G1 bulges almost always occur in combination with a type II tight turn. The functional roles of beta bulges probably include compensating for the effects of a single-residue insertion or deletion within beta structure and providing the strong local twist required for form closed beta barrel structures.

Full Text

Duke Authors

Cited Authors

  • Richardson, JS; Getzoff, ED; Richardson, DC

Published Date

  • June 1978

Published In

Volume / Issue

  • 75 / 6

Start / End Page

  • 2574 - 2578

PubMed ID

  • 275827

Pubmed Central ID

  • PMC392604

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.75.6.2574


  • eng

Conference Location

  • United States