1dun
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(New page: 200px<br /><applet load="1dun" size="450" color="white" frame="true" align="right" spinBox="true" caption="1dun, resolution 1.9Å" /> '''EIAV DUTPASE NATIVE''...)
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Revision as of 11:28, 20 November 2007
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EIAV DUTPASE NATIVE
Overview
The X-ray structures of dUTPase from equine infectious anaemia virus, (EIAV) in unliganded and complexed forms have been determined to 1.9 and, 2.0 A resolution, respectively. The structures were solved by molecular, replacement using Escherichia coli dUTPase as search model. The, exploitation of a relatively novel refinement approach for the initial, model, combining maximum likelihood refinement with stereochemically, unrestrained updating of the model, proved to be of crucial importance and, should be of general relevance.EIAV dUTPase is a homotrimer where each, subunit folds into a twisted antiparallel beta-barrel with the N and, C-terminal portions interacting with adjacent subunits. The C-terminal 14, and 17 amino acid residues are disordered in the crystal structure of the, unliganded and complexed enzyme, respectively. Interactions along the, 3-fold axis include a water-containing volume (size 207 A3) which has no, contact with bulk solvent.It has earlier been shown that a divalent metal, ion is essential for catalysis. For the first time, a putative binding, site for such a metal ion, in this case Sr2+, is established. The, positions of the inhibitor (the non-hydrolysable substrate analogue dUDP), and the metal ion in the complex are consistent with the location of the, active centre established for trimeric dUTPase structures, in which, subunit interfaces form three surface clefts lined with evolutionary, conserved residues. However, a detailed comparison of the active sites of, the EIAV and E. coli enzymes reveals some structural differences. The, viral enzyme undergoes a small conformational change in the uracil-binding, beta-hairpin structure upon dUDP binding not observed in the other known, dUTPase structures.
About this Structure
1DUN is a Single protein structure of sequence from Equine infectious anemia virus. Active as dUTP diphosphatase, with EC number 3.6.1.23 Full crystallographic information is available from OCA.
Reference
Crystal structure of dUTPase from equine infectious anaemia virus; active site metal binding in a substrate analogue complex., Dauter Z, Persson R, Rosengren AM, Nyman PO, Wilson KS, Cedergren-Zeppezauer ES, J Mol Biol. 1999 Jan 15;285(2):655-73. PMID:9878436
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