Discovery of three novel lipase (lipA(1), lipA(2), and lipA(3)) and lipase-specific chaperone (lipB) genes present in Acinetobacter sp DYL129

摘要

A microbe isolated from a soil sample obtained on Deog-yu Mountain in Korea, was found to produce an extracellular lipase. This microbe, which was designated as DYL129, was identified as an Acinetobacter sp. based on phylogenetic analysis of its 16S rDNA. A genomic library was constructed by using DYL129 fragment digested with HindIII and a recombinant plasmid, pLip-1, was selected for further analysis by colony polymerase chain reaction (PCR). Sequencing of a 3.8-kb insert in the pLip-1 clone revealed the presence of one incomplete and three complete open reading frames (ORFs). The ORFs were predicted to encode a partial lipase, two putative lipases and a 50S ribosomal protein. Genome-walking PCR also identified transcripts encoding a complete lipase chaperone and three lipaseA proteins. The lipase structural gene present in Acinetobacter sp. DYL129 was similar to the lipase structural gene found in Acinetobacter calcoaceticus BD413 (lipBA). However, the three lipase genes were located downstream of the chaperone gene in Acinetobacter sp. DYL129 (lipBA(1)A (2)A(3)), which differs from the location of these genes in A. calcoaceticus BD413. Although the amino acid sequences of these lipases (LipA(1), LipA(2), and LipA(3)) differed, both strains had a common "GHSHG" consensus motif, which is the conserved active-site pentapeptide of lipaseA. Moreover, all three lipases were found to share a conserved domain, the so-called alpha/beta hydrolase fold.