Molecular Characterization and Heterologous Expression of Quinate Dehydrogenase Gene from Gluconobacter oxydans IFO3244

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A. S. Vangnai^1*, W. Promden¹, W. De-eknamkul², K. Matsushita³, and H. Toyama⁴

¹Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; fax: +662-218-5418; E-mail: alisa.v@chula.ac.th; p_worrawat@yahoo.com

²Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand; fax: +662-254-5195; E-mail: dwanchai@chula.ac.th

³Laboratory of Applied Microbiology, Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; fax: +81-83-933-5859; E-mail: kazunobu@yamaguchi-u.ac.jp

⁴Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, Senbaru, Nishihara-cho, Okinawa 903-0213, Japan; fax: +81-98-895-8805; E-mail: toyama@agr.u-ryukyu.ac.jp

^* To whom correspondence should be addressed.

Received May 12, 2009; Revision received June 4, 2009

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The quinate dehydrogenase (QDH) from Gluconobacter oxydans IFO3244 exhibits high affinity for quinate, suggesting its application in shikimate production. Nucleotide sequence analysis of the qdh gene revealed a full-length of 2475-bp encoding an 824-amino acid protein. The qdh gene has the unusual TTG translation initiation codon. Conserved regions and a signature sequence for the quinoprotein family were observed. Phylogenetic analysis demonstrated relatedness of QDH from G. oxydans to other quinate/shikimate dehydrogenases with the highest similarity (56%) with that of Acinetobacter calcoaceticus ADP1 and lower similarity (36%) with a membrane-bound glucose dehydrogenase of Escherichia coli. The function of the gene coding for QDH was confirmed by heterologous gene expression in pyrroloquinoline quinone-synthesizing Pseudomonas putida HK5.

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KEY WORDS: quinate dehydrogenase gene, heterologous gene expression, Gluconobacter oxydans, pyrroloquinoline quinone

DOI: 10.1134/S0006297910040085

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