Cloning and expression of a xylitol-4-dehydrogenase gene from Pantoea ananatis

Johannes Aarnikunnas, A Pihlajaniemi, Airi Palva, Matti Leisola, Antti Nyyssölä

    Research output: Contribution to journalArticleScientificpeer-review

    Abstract

    "The Pantoea ananatis ATCC 43072 mutant strain is capable of growing with xylitol as the sole carbon source. The xylitol-4-dehydrogenase (XDH) catalyzing the oxidation of xylitol to L-xylulose was isolated from the cell extract of this strain. The N-terminal amino acid sequence of the purified protein was determined, and an oligonucleotide deduced from this peptide sequence was used to isolate the xylitol-4-dehydrogenase gene (xdh) from a P. ananatis gene library. Nucleotide sequence analysis revealed an open reading frame of 795 bp, encoding the xylitol-4-dehydrogenase, followed by a 5' region of another open reading frame encoding an unknown protein. Results from a Northern analysis of total RNA isolated from P. ananatis ATCC 43072 suggested that xdh is transcribed as part of a polycistronic mRNA. Reverse transcription-PCR analysis of the transcript confirmed the operon structure and suggested that xdh was the first gene of the operon. Homology searches revealed that the predicted amino acid sequence of the P. ananatis XDH shared significant identity (38 to 51%) with members of the short-chain dehydrogenase/reductase family. The P. ananatis xdh gene was successfully overexpressed in Escherichia coli, XDH was purified to homogeneity, and some of its enzymatic properties were determined. The enzyme had a preference for NAD(+) as the cosubstrate, and in contrast to previous reports, the enzyme also showed a side activity for the D-form of xylulose. Xylitol was converted to L-xylulose with a high yield (> 80%) by the resting recombinant cells, and the L-xylulose was secreted into the medium. No evidence of D-xylulose being synthesized by the recombinant cells was found."
    Original languageEnglish
    JournalApplied and Environmental Microbiology
    Volume72
    Issue number1
    Pages (from-to)368-377
    Number of pages10
    ISSN0099-2240
    Publication statusPublished - 2006
    MoE publication typeA1 Journal article-refereed

    Fields of Science

    • 413 Veterinary science
    • bakteerit
    • Pantoea ananatis
    • geenit

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