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

Abstract

The quinate dehydrogenase (QDH) from Gluconobacter oxydans IFO3244 exhibits high affinity for quinate, sug gesting 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.