1dxq
From Proteopedia
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CRYSTAL STRUCTURE OF MOUSE NAD[P]H-QUINONE OXIDOREDUCTASE
Overview
NAD(P)H/quinone acceptor oxidoreductase (QR1, NQO1, formerly, DT-diaphorase; EC ) protects animal cells from the deleterious and, carcinogenic effects of quinones and other electrophiles. In this paper we, report the apoenzyme structures of human (at 1.7-A resolution) and mouse, (2.8 A) QR1 and the complex of the human enzyme with the substrate, duroquinone (2.5 A) (2,3,5, 6-tetramethyl-p-benzoquinone). In addition to, providing a description and rationale of the structural and catalytic, differences among several species, these structures reveal the changes, that accompany substrate or cofactor (NAD) binding and release., Tyrosine-128 and the loop spanning residues 232-236 close the binding, site, partially occupying the space left vacant by the departing molecule, (substrate or cofactor). These changes highlight the exquisite control of, access to the catalytic site that is required by the ping-pong mechanism, in which, after reducing the flavin, NAD(P)(+) leaves the catalytic site, and allows substrate to bind at the vacated position. In the human, QR1-duroquinone structure one ring carbon is significantly closer to the, flavin N5, suggesting a direct hydride transfer to this atom.
About this Structure
1DXQ is a Single protein structure of sequence from Mus musculus with FAD as ligand. Active as NAD(P)H dehydrogenase (quinone), with EC number 1.6.5.2 Full crystallographic information is available from OCA.
Reference
Structures of recombinant human and mouse NAD(P)H:quinone oxidoreductases: species comparison and structural changes with substrate binding and release., Faig M, Bianchet MA, Talalay P, Chen S, Winski S, Ross D, Amzel LM, Proc Natl Acad Sci U S A. 2000 Mar 28;97(7):3177-82. PMID:10706635
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