The β-link motif in protein architecture

Leader, D.P. and Milner-White, E.J. (2021) The β-link motif in protein architecture. Acta Crystallographica Section D: Structural Biology, 77(8), pp. 1040-1049. (doi: 10.1107/S2059798321006768)

Abstract

The β-link is a composite protein motif consisting of a G1β β-bulge and a type II β-turn, and is generally found at the end of two adjacent strands of antiparallel β-sheet. The 1,2-positions of the β-bulge are also the 3,4-positions of the β-turn, with the result that the N-terminal portion of the polypeptide chain is orientated at right angles to the β-sheet. Here, it is reported that the β-link is frequently found in certain protein folds of the SCOPe structural classification at specific locations where it connects a β-sheet to another area of a protein. It is found at locations where it connects one β-sheet to another in the β-sandwich and related structures, and in small (four-, five- or six-stranded) β-barrels, where it connects two β-strands through the polypeptide chain that crosses an open end of the barrel. It is not found in larger (eight-stranded or more) β-barrels that are straightforward β-meanders. In some cases it initiates a connection between a single β-sheet and an α-helix. The β-link also provides a framework for catalysis in serine proteases, where the catalytic serine is part of a conserved β-link, and in cysteine proteases, including Mpro of human SARS-CoV-2, in which two residues of the active site are located in a conserved β-link.

• Item Type: Articles
• Keywords: β-link, β-barrel, β-sandwich, β-bulge, β-turn, serine proteases, SARS-CoV-2 protease.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Milner-White, Professor E and Leader, Dr David
• Authors: Leader, D.P., and Milner-White, E.J.
• College/School: College of Medical Veterinary and Life Sciences; College of Medical Veterinary and Life Sciences > School of Life Sciences
• Journal Name: Acta Crystallographica Section D: Structural Biology
• Publisher: International Union of Crystallography
• ISSN: 2059-7983
• ISSN (Online): 2059-7983
• First Published: First published in Acta Crystallographica Section D: Structural Biology 77(8): 1040-1049
• Publisher Policy: Reproduced under a Creative Commons License