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Title: Enhanced rigid-bond restraints

Abstract

An extension is proposed to the rigid-bond description of atomic thermal motion in crystals. The rigid-bond model [Hirshfeld (1976 ▶). Acta Cryst. A32, 239–244] states that the mean-square displacements of two atoms are equal in the direction of the bond joining them. This criterion is widely used for verification (as intended by Hirshfeld) and also as a restraint in structure refinement as suggested by Rollett [Crystallographic Computing (1970 ▶), edited by F. R. Ahmed et al., pp. 167–181. Copenhagen: Munksgaard]. By reformulating this condition, so that the relative motion of the two atoms is required to be perpendicular to the bond, the number of restraints that can be applied per anisotropic atom is increased from about one to about three. Application of this condition to 1,3-distances in addition to the 1,2-distances means that on average just over six restraints can be applied to the six anisotropic displacement parameters of each atom. This concept is tested against very high resolution data of a small peptide and employed as a restraint for protein refinement at more modest resolution (e.g. 1.7 Å)

Authors:
; ;  [1]
  1. Department of Structural Chemistry, University of Göttingen, Tammannstrasse 4, D-37077 Göttingen (Germany)
Publication Date:
OSTI Identifier:
22347673
Resource Type:
Journal Article
Journal Name:
Acta Crystallographica. Section A, Foundations of Crystallography
Additional Journal Information:
Journal Volume: 68; Journal Issue: Pt 4; Other Information: PMCID: PMC3377366; PUBLISHER-ID: pc5011; OAI: oai:pubmedcentral.nih.gov:3377366; Copyright (c) Andrea Thorn et al. 2012; This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0108-7673
Country of Publication:
Denmark
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMS; CRYSTALS; DISTANCE; RESOLUTION; VERIFICATION

Citation Formats

Thorn, Andrea, Dittrich, Birger, and Sheldrick, George M., E-mail: gsheldr@shelx.uni-ac.gwdg.de. Enhanced rigid-bond restraints. Denmark: N. p., 2012. Web. doi:10.1107/S0108767312014535.
Thorn, Andrea, Dittrich, Birger, & Sheldrick, George M., E-mail: gsheldr@shelx.uni-ac.gwdg.de. Enhanced rigid-bond restraints. Denmark. doi:10.1107/S0108767312014535.
Thorn, Andrea, Dittrich, Birger, and Sheldrick, George M., E-mail: gsheldr@shelx.uni-ac.gwdg.de. Sun . "Enhanced rigid-bond restraints". Denmark. doi:10.1107/S0108767312014535.
@article{osti_22347673,
title = {Enhanced rigid-bond restraints},
author = {Thorn, Andrea and Dittrich, Birger and Sheldrick, George M., E-mail: gsheldr@shelx.uni-ac.gwdg.de},
abstractNote = {An extension is proposed to the rigid-bond description of atomic thermal motion in crystals. The rigid-bond model [Hirshfeld (1976 ▶). Acta Cryst. A32, 239–244] states that the mean-square displacements of two atoms are equal in the direction of the bond joining them. This criterion is widely used for verification (as intended by Hirshfeld) and also as a restraint in structure refinement as suggested by Rollett [Crystallographic Computing (1970 ▶), edited by F. R. Ahmed et al., pp. 167–181. Copenhagen: Munksgaard]. By reformulating this condition, so that the relative motion of the two atoms is required to be perpendicular to the bond, the number of restraints that can be applied per anisotropic atom is increased from about one to about three. Application of this condition to 1,3-distances in addition to the 1,2-distances means that on average just over six restraints can be applied to the six anisotropic displacement parameters of each atom. This concept is tested against very high resolution data of a small peptide and employed as a restraint for protein refinement at more modest resolution (e.g. 1.7 Å)},
doi = {10.1107/S0108767312014535},
journal = {Acta Crystallographica. Section A, Foundations of Crystallography},
issn = {0108-7673},
number = Pt 4,
volume = 68,
place = {Denmark},
year = {2012},
month = {7}
}