2aud
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(New page: 200px<br /><applet load="2aud" size="450" color="white" frame="true" align="right" spinBox="true" caption="2aud, resolution 2.1Å" /> '''Unliganded HincII'''<...)
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Revision as of 06:15, 21 November 2007
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Unliganded HincII
Overview
The 2.1A crystal structure of the unliganded type II restriction, endonuclease, HincII, is described. Although the asymmetric unit contains, only a single monomer, crystal lattice contacts bring two monomers, together to form a dimer very similar to that found in the DNA bound form., Comparison with the published DNA bound structure reveals that the DNA, binding pocket is expanded in the unliganded structure. Comparison of the, unliganded and DNA liganded structures reveals a simple rotation of, subunits by 11 degrees each, or 22 degrees total, to a more closed, structure around the bound DNA. Comparison of this conformational change, to that observed in the other type II restriction endonucleases where DNA, bound and unliganded forms have both been characterized, shows, considerable variation in the types of conformational changes that can, occur. The conformational changes in three can be described by a simple, rotation of subunits, while in two others both rotation and translation of, subunits relative to one another occurs. In addition, the endonucleases, having subunits that undergo the greatest amount of rotation upon DNA, binding are found to be those that distort the bound DNA the least, suggesting that DNA bending may be less facile in dimers possessing, greater flexibility.
About this Structure
2AUD is a Single protein structure of sequence from Haemophilus influenzae. Active as Type II site-specific deoxyribonuclease, with EC number 3.1.21.4 Full crystallographic information is available from OCA.
Reference
DNA-induced conformational changes in type II restriction endonucleases: the structure of unliganded HincII., Little EJ, Horton NC, J Mol Biol. 2005 Aug 5;351(1):76-88. PMID:15993893
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