title: Characterization of genes involved in D-sorbitol oxidation in thermotolerant Gluconobacter frateurii.
abstract: Further upstream of sldSLC, genes for FAD-dependent D-sorbitol dehydrogenase in Gluconobacter frateurii, three additional genes (sldR, xdhA, and perA) are found: for a transcriptional regulator, NAD(P)-dependent xylitol dehydrogenase, and a transporter protein, a member of major facilitator superfamily, respectively. xdhA and perA but not sldR were found to be in the same transcriptional unit. Disruption of sldR resulted in a dramatic decrease in sldSLC promoter activity, indicating that it is an activator for sldSLC expression. The recombinant protein of XdhA expressed in Escherichia coli showed NAD-dependent dehydrogenase activities with xylitol and D-sorbitol, but a mutant strain defective in this gene showed similar activities with both substrates as compared to the wild-type strain. Nonetheless, the growth of the xdhA mutant strain on D-sorbitol and xylitol was retarded, and so was that of a mutant strain defective in perA. These results indicate that xdhA and perA are involved in assimilation of D-sorbitol and xylitol.
authors.affiliation: Department of Science and Technology, Nongkhai Campus, Khon Kaen University, Nongkhai 43000, Thailand.
authors.forename: Wichai
authors.initials: W
authors.lastname: Soemphol
authors.forename: Natsaran
authors.initials: N
authors.lastname: Saichana
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yakushi
authors.forename: Osao
authors.initials: O
authors.lastname: Adachi
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Matsushita
authors.forename: Hirohide
authors.initials: H
authors.lastname: Toyama
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D050542:D-Xylulose Reductase / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli; D020576:Gluconobacter / Q000201:enzymology / Q000235:genetics*; D006358:Hot Temperature; D007064:L-Iditol 2-Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013012:Sorbitol / Q000378:metabolism*; D014158:Transcription, Genetic; D014993:Xylitol / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D011994:Recombinant Proteins; D013012:Sorbitol; D009249:NADP; D007064:L-Iditol 2-Dehydrogenase; D050542:D-Xylulose Reductase; D014993:Xylitol