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Title: An introduction to stereochemical restraints

Abstract

A brief summary of the types of restraint defined in refinement dictionaries. At the resolution available from most macromolecular crystals, the X-ray data alone are insufficient to lead to a chemically reasonable structure, so stereochemical restraints are essential. These usually restrain bond lengths, bond angles, planes and chiral volumes. The definition of these restraints and where the values come from are described. A dictionary entry contains information about the atom types, their connectivity and all the appropriate restraints. Torsion angles are not usually restrained, but they do have optimum values. In the special case of flexible five- and six-membered rings, including pentose and hexose sugars, the ring pucker is defined by combinations of torsion angles and the pucker affects the position of substituents.

Authors:
 [1]
  1. MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH (United Kingdom)
Publication Date:
OSTI Identifier:
22348007
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica. Section D: Biological Crystallography; Journal Volume: 63; Journal Issue: Pt 1; Other Information: PMCID: PMC2483478; PUBLISHER-ID: ba5098; PMID: 17164527; OAI: oai:pubmedcentral.nih.gov:2483478; Copyright (c) International Union of Crystallography 2007; This is an open-access article distributed under the terms described at http://journals.iucr.org/services/termsofuse.html.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
Denmark
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMS; BOND ANGLE; BOND LENGTHS; CRYSTALS; PROTEIN STRUCTURE; RESOLUTION; RINGS; SACCHAROSE; STEREOCHEMISTRY; TORSION

Citation Formats

Evans, Philip R., E-mail: pre@mrc-lmb.cam.ac.uk. An introduction to stereochemical restraints. Denmark: N. p., 2007. Web. doi:10.1107/S090744490604604X.
Evans, Philip R., E-mail: pre@mrc-lmb.cam.ac.uk. An introduction to stereochemical restraints. Denmark. doi:10.1107/S090744490604604X.
Evans, Philip R., E-mail: pre@mrc-lmb.cam.ac.uk. Mon . "An introduction to stereochemical restraints". Denmark. doi:10.1107/S090744490604604X.
@article{osti_22348007,
title = {An introduction to stereochemical restraints},
author = {Evans, Philip R., E-mail: pre@mrc-lmb.cam.ac.uk},
abstractNote = {A brief summary of the types of restraint defined in refinement dictionaries. At the resolution available from most macromolecular crystals, the X-ray data alone are insufficient to lead to a chemically reasonable structure, so stereochemical restraints are essential. These usually restrain bond lengths, bond angles, planes and chiral volumes. The definition of these restraints and where the values come from are described. A dictionary entry contains information about the atom types, their connectivity and all the appropriate restraints. Torsion angles are not usually restrained, but they do have optimum values. In the special case of flexible five- and six-membered rings, including pentose and hexose sugars, the ring pucker is defined by combinations of torsion angles and the pucker affects the position of substituents.},
doi = {10.1107/S090744490604604X},
journal = {Acta Crystallographica. Section D: Biological Crystallography},
number = Pt 1,
volume = 63,
place = {Denmark},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}