Rings and ribbons in protein structures: characterization using helical parameters and Ramachandran plots for repeating dipeptides

Hayward, S., Leader, D.P., Al-Shubailly, F. and Milner-White, E.J. (2014) Rings and ribbons in protein structures: characterization using helical parameters and Ramachandran plots for repeating dipeptides. Proteins: Structure Function and Bioinformatics, 82(2), pp. 230-239. (doi:10.1002/prot.24357)

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Publisher's URL: http://dx.doi.org/10.1002/prot.24357

Abstract

Helical parameters displayed on a Ramachandran plot allow peptide structures with successive residues having identical main chain conformations to be studied. We investigate repeating dipeptide main chain conformations and present Ramachandran plots encompassing the range of possible structures. Repeating dipeptides fall into the categories: rings, ribbons, and helices. Partial rings occur in the form of “nests” and “catgrips”; many nests are bridged by an oxygen atom hydrogen bonding to the main chain NH groups of alternate residues, an interaction optimized by the ring structure of the nest. A novel recurring feature is identified that we name unpleated β, often situated at the ends of a β-sheet strand. Some are partial rings causing the polypeptide to curve gently away from the sheet; some are straight. They lack β-pleat and almost all incorporate a glycine. An example is the first glycine in the GxxxxGK motif of P-loop proteins. Ribbons in repeating dipeptides can be either flat, as seen in repeated type II and type II′ β-turns, or twisted, as in multiple type I and type I′ β-turns. Hexa- and octa-peptides in such twisted ribbons occur frequently in proteins, predominantly with type I β-turns, and are the same as the “β-bend ribbons” hitherto identified only in short peptides. One is seen in the GTPase-activating protein for Rho in the active, but not the inactive, form of the enzyme. It forms a β-bend ribbon, which incorporates the catalytic arginine, allowing its side chain guanidino group to approach the active site and enhance enzyme activity

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Leader, Dr David and Milner-White, Professor E
Authors: Hayward, S., Leader, D.P., Al-Shubailly, F., and Milner-White, E.J.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:Proteins: Structure Function and Bioinformatics
Publisher:John Wiley & Sons
ISSN:0887-3585
ISSN (Online):1097-0134

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