Probing the substrate binding site of Candida tenuis xylose reductase (AKR2B5) with site-directed mutagenesis
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Probing the substrate binding site of Candida tenuis xylose reductase (AKR2B5) with site-directed mutagenesis.
Little is known about how substrates bind to CtXR (Candida tenuis xylose reductase; AKR2B5) and other members of the AKR (aldo-keto reductase) protein superfamily. Modelling of xylose into the active site of CtXR suggested that Trp23, Asp50 and Asn309 are the main components of pentose-specific substrate-binding recognition. Kinetic consequences of site-directed substitutions of these residues ...
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CtXR (xylose reductase from the yeast Candida tenuis; AKR2B5) can utilize NADPH or NADH as co-substrate for the reduction of D-xylose into xylitol, NADPH being preferred approx. 33-fold. X-ray structures of CtXR bound to NADP+ and NAD+ have revealed two different protein conformations capable of accommodating the presence or absence of the coenzyme 2'-phosphate group. Here we have used site-dir...
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Lys-80 of Candida tenuis xylose reductase (AKR2B5) is conserved throughout the aldo-keto reductase protein superfamily and may prime the nearby Tyr-51 for general acid catalysis to NAD(P)H-dependent carbonyl group reduction. We have examined the catalytic significance of side-chain substitutions in two AKR2B5 mutants, Lys-80-->Ala (K80A) and Asp-46-->Asn Lys-80-->Ala (D46N K80A), using steady-s...
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ژورنال
عنوان ژورنال: Biochemical Journal
سال: 2005
ISSN: 0264-6021,1470-8728
DOI: 10.1042/bj20050831