[Cloning, expression and characterization of a lipase gene, lipC24, from Burkholderia sp. ZYB002].

Objective: We cloned a lipase gene, lipC24, from Burkholderia sp. ZYB002 and characterized the recombinant lipase LipC24.

Method: Based on the known genomic DNA sequence from Burkholderia cecapia JK321, we designed a pair of specific primers for the lipC24 gene and then obtained the full length of lipC24 gene. The lipC24 gene fragment enconding the mature peptide LipC24 was then subcloned into expression plasmid, pACYC-Duet-lipB, and expressed in E. coli. The recombinant protein, LipC24, was purified to homogeneity by HisTrap HP chromatography column and HiTrap DEAE FF chromatography column.

Results: We expressed the lipC24 gene from Burkholderia sp. ZYB002 in E. coli Origami 2(DE3). Nucleotide sequencing revealed that the lipC24 gene had an open reading frame of 1317 bp, and the deduced amino acid sequence of LipC24 corresponded to 438 amino acid residues, including a conserved -G-X1-S-X2-G- motif. The relative molecular weight of the purified LipC24 was about 45 kDa. The purified LipC24 displayed hydrolysis activity to various 4-nitrophenyl esters and substrate preference for the medium chain length 4-nitrophenyl-esters. The optimal temperature was 40°C and the optimal pH was 7.5. The lipase was stable between pH 7.0 and 8.0 for 24 hours. However, the half-life was only 16 min at 40°C.

Conclusion: The LipC24 was a 45 kDa protein, a mesotherm and neutral lipase.