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BioMed Research International
Volume 2013 (2013), Article ID 326914, 8 pages
http://dx.doi.org/10.1155/2013/326914
Research Article

Interplay between Peptide Bond Geometrical Parameters in Nonglobular Structural Contexts

1Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134 Napoli, Italy
2Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
3Division of Molecular Biosciences, Imperial College South Kensington Campus, London SW7 2AZ, UK

Received 10 September 2013; Accepted 29 November 2013

Academic Editor: Kei Yura

Copyright © 2013 Luciana Esposito et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Several investigations performed in the last two decades have unveiled that geometrical parameters of protein backbone show a remarkable variability. Although these studies have provided interesting insights into one of the basic aspects of protein structure, they have been conducted on globular and water-soluble proteins. We report here a detailed analysis of backbone geometrical parameters in nonglobular proteins/peptides. We considered membrane proteins and two distinct fibrous systems (amyloid-forming and collagen-like peptides). Present data show that in these systems the local conformation plays a major role in dictating the amplitude of the bond angle N- -C and the propensity of the peptide bond to adopt planar/nonplanar states. Since the trends detected here are in line with the concept of the mutual influence of local geometry and conformation previously established for globular and water-soluble proteins, our analysis demonstrates that the interplay of backbone geometrical parameters is an intrinsic and general property of protein/peptide structures that is preserved also in nonglobular contexts. For amyloid-forming peptides significant distortions of the N- -C bond angle, indicative of sterical hidden strain, may occur in correspondence with side chain interdigitation. The correlation between the dihedral angles in collagen-like models may have interesting implications for triple helix stability.