2b5h
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(New page: 200px<br /><applet load="2b5h" size="450" color="white" frame="true" align="right" spinBox="true" caption="2b5h, resolution 1.50Å" /> '''1.5 A Resolution Cry...)
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Revision as of 06:26, 21 November 2007
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1.5 A Resolution Crystal Structure of Recombinant R. Norvegicus Cysteine Dioxygenase
Overview
Cysteine dioxygenase is a mononuclear iron-dependent enzyme responsible, for the oxidation of cysteine with molecular oxygen to form cysteine, sulfinate. This reaction commits cysteine to either catabolism to sulfate, and pyruvate or the taurine biosynthetic pathway. Cysteine dioxygenase is, a member of the cupin superfamily of proteins. The crystal structure of, recombinant rat cysteine dioxygenase has been determined to 1.5-A, resolution, and these results confirm the canonical cupin beta-sandwich, fold and the rare cysteinyltyrosine intramolecular cross-link (between, Cys(93) and Tyr(157)) seen in the recently reported murine cysteine, dioxygenase structure. In contrast to the catalytically inactive, mononuclear Ni(II) metallocenter present in the murine structure, crystallization of a catalytically competent preparation of rat cysteine, dioxygenase revealed a novel tetrahedrally coordinated mononuclear iron, center involving three histidines (His(86), His(88), and His(140)) and a, water molecule. Attempts to acquire a structure with bound ligand using, either cocrystallization or soaking crystals with cysteine revealed the, formation of a mixed disulfide involving Cys(164) near the active site, which may explain previously observed substrate inhibition. This work, provides a framework for understanding the molecular mechanisms involved, in thiol dioxygenation and sets the stage for exploration of the chemistry, of both the novel mononuclear iron center and the catalytic role of the, cysteinyl-tyrosine linkage.
About this Structure
2B5H is a Single protein structure of sequence from Rattus norvegicus with FE as ligand. Active as Cysteine dioxygenase, with EC number 1.13.11.20 Full crystallographic information is available from OCA.
Reference
Crystal structure of mammalian cysteine dioxygenase. A novel mononuclear iron center for cysteine thiol oxidation., Simmons CR, Liu Q, Huang Q, Hao Q, Begley TP, Karplus PA, Stipanuk MH, J Biol Chem. 2006 Jul 7;281(27):18723-33. Epub 2006 Apr 11. PMID:16611640
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