Cloning, sequencing and expression of a chromosomal aldehyde dehydrogenase-encoding gene from Halomonas salina AS11

Thanya Sripo, D. of Biochemistry, F. of Sci., PSU.
Amornrat Phongdara, Assoc. Prof., D. of Biochemistry, F. of Sci., PSU.
Chokchai Wanapu, School of Agriculture Tech., Suranaree U. of Technology, Nakon Ratchasrima
Corresponding e-mail : pamornra@ratree.psu.ac.th

Grant : GREC (NSTDA)
Published : Research Report
Key words : Halomonas salina, halophilic, aldehyde, dehydrogenase

Bacteria from prawn pond's sediment were screened on medium containing NaCl concen tration 5-25%. Twenty-two of isolated halophilic bacteria show aldehyde dehydrogenase activity. Phenotypic and phylogenetic studies indicated that AS11 referred to Halomonas salina. A genomic library was constructed and screened by using synthetic oligonucleotide corresponding to the amino acid sequences of the conserved sequences of aldehyde dehydrogenase gene family. The positive clone was subcloned and sequenced. The aldh gene encoding an aldehyde dehydrogenase of 54-kDa has been cloned from Halomonas salina AS11. The primary structure of the aldh gene consisted of 1,521-bp encoding 506 amino acid residues. Comparison of the deduced amino acid sequence of the cloned aldehyde dehydrogenase gene product (aldh) with other dehydrogenases revealed a high homology (76%identity) with NAD-dependent acetaldehyde dehydrogenase gene from Pseudomo- nas aeruginosa.

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