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dc.contributor.authorZhang, M.
dc.contributor.authorJiang, S.
dc.contributor.authorZheng, Z.
dc.contributor.authorLi, Xingjiang
dc.contributor.authorLuo, S.
dc.contributor.authorWu, X.
dc.identifier.citationZhang, M. and Jiang, S. and Zheng, Z. and Li, X. and Luo, S. and Wu, X. 2015. Cloning, expression, and characterization of a novel xylose reductase from Rhizopus oryzae. Journal of Basic Microbiology. 55 (7): pp. 907-921.

Rhizopus oryzae is valuable as a producer of organic acids via lignocellulose catalysis. R. oryzae metabolizes xylose, which is one component of lignocellulose hydrolysate. In this study, a novel NADPH-dependent xylose reductase gene from R. oryzae AS 3.819 (Roxr) was cloned and expressed in Pichia pastoris GS115. Homology alignment suggested that the 320-residue protein contained domains and active sites belonging to the aldo/keto reductase family. SDS–PAGE demonstrated that the recombinant xylose reductase has a molecular weight of approximately 37 kDa. The optimal catalytic pH and temperature of the purified recombinant protein were 5.8 and 50 °C, respectively. The recombinant protein was stable from pH 4.4 to 6.5 and at temperatures below 42 °C. The recombinant enzyme has bias for D-xylose and L-arabinose as substrates and NADPH as its coenzyme. Real-time quantitative reverse transcription PCR tests suggested that native Roxr expression is regulated by a carbon catabolite repression mechanism. Site-directed mutagenesis at two possible key sites involved in coenzyme binding, Thr226 [RIGHTWARDS ARROW] Glu226 and Val274 [RIGHTWARDS ARROW] Asn274, were performed, respectively. The coenzyme specificity constants of the resulted RoXRT226E and RoXRV274N for NADH increased 18.2-fold and 2.4-fold, which suggested possibility to improve the NADH preference of this enzyme through genetic modification.

dc.publisherWiley-VCH Verlag
dc.titleCloning, expression, and characterization of a novel xylose reductase from Rhizopus oryzae
dc.typeJournal Article
dcterms.source.titleJournal of Basic Microbiology
curtin.departmentDepartment of Chemical Engineering
curtin.accessStatusFulltext not available

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