Cloning and expression of lipP, a gene encoding a cold-adapted lipase from Moritella sp.2-5-10-1.

摘要

A gene (lipP, 837 bp in length) coding for a cold-adapted lipase of psychrophilic bacterium Moritella sp. 2-5-10-1 isolated from Antarctic region was cloned and sequenced in this study. The deduced amino acid sequence revealed a protein of 278 amino acid residues with a mol. wt. of 30 521 Da. The primary structure of the lipase deduced from the nucleotide sequence showed consensus pentapeptide containing the active serine [Gly-Trp-Ser-Leu-Gly] and a conserved His-Gly dipeptide in the N-terminal part of the enzyme. These sequences were found to be involved in the lipase active site conformation. Structure factors that would allow proper enzyme flexibility at low temp. were discussed. It was suggested that the changes in the primary structure of the psychrophilic lipases compared with the thermophilic ones could account for their ability to catalyse lipolysis at temp. close to 0 degrees C. For expression, the sequence corresponding to the cold-adapted lipase of strain 2-5-10-1 was subcloned into the pET-28a expression vector to construct a recombinant lipase protein. Expression of the lipase by Escherichia coli BL21 (DE3) cells was observed as clear halos on 1% (vol/vol) tributyrin upon induction with IPTG at 25 degrees C.