1iyz
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1iyz" size="450" color="white" frame="true" align="right" spinBox="true" caption="1iyz, resolution 2.80Å" /> '''Crystal Structures o...)
Next diff →
Revision as of 20:41, 24 November 2007
|
Crystal Structures of the Quinone Oxidoreductase from Thermus thermophilus HB8 and Its Complex with NADPH
Overview
The crystal structures of the zeta-crystalline-like soluble quinone, oxidoreductase from Thermus thermophilus HB8 (QOR(Tt)) and of its complex, with NADPH have been determined at 2.3- and 2.8-A resolutions, respectively. QOR(Tt) is composed of two domains, and its overall fold is, similar to the folds of Escherichia coli quinone oxidoreductase (QOR(Ec)), and horse liver alcohol dehydrogenase. QOR(Tt) forms a homodimer in the, crystal by interaction of the betaF-strands in domain II, forming a large, beta-sheet that crosses the dimer interface. High thermostability of, QOR(Tt) was evidenced by circular dichroic measurement. NADPH is located, between the two domains in the QOR(Tt)-NADPH complex. The disordered, segment involved in the coenzyme binding of apo-QOR(Tt) becomes ordered, upon NADPH binding. The segment covers an NADPH-binding cleft and may, serve as a lid. The 2'-phosphate group of the adenine of NADPH is, surrounded by polar and positively charged residues in QOR(Tt), suggesting, that QOR(Tt) binds NADPH more readily than NADH. The putative, substrate-binding site of QOR(Tt), unlike that of QOR(Ec), is largely, blocked by nearby residues, permitting access only to small substrates., This may explain why QOR(Tt) has weak p-benzoquinone reduction activity, and is inactive with such large substrates of QOR(Ec) as, 5-hydroxy-1,4-naphthoquinone and phenanthraquinone.
About this Structure
1IYZ is a Single protein structure of sequence from Thermus thermophilus with NDP as ligand. Active as NADPH:quinone reductase, with EC number 1.6.5.5 Full crystallographic information is available from OCA.
Reference
Crystal structures of the quinone oxidoreductase from Thermus thermophilus HB8 and its complex with NADPH: implication for NADPH and substrate recognition., Shimomura Y, Kakuta Y, Fukuyama K, J Bacteriol. 2003 Jul;185(14):4211-8. PMID:12837796
Page seeded by OCA on Sat Nov 24 22:48:31 2007
