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1iz0

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1iz0, resolution 2.30Å ()
Ligands:
Non-Standard Residues:
Activity: NADPH:quinone reductase, with EC number 1.6.5.5
Domains: ADH_zinc_N, Qor
Related: 1iyz
Resources: FirstGlance, OCA, PDBsum, RCSB, TOPSAN
Coordinates: save as pdb, mmCIF, xml



Crystal Structures of the Quinone Oxidoreductase from Thermus thermophilus HB8 and Its Complex with NADPH

Publication Abstract from PubMed

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.

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

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

About this Structure

1IZ0 is a 1 chain structure of sequence from Thermus thermophilus. 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

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