engleski

GDS(L) LIPASE FROM Streptomyces coelicolor: CLONING, PURIFICATION AND BASIC PROPERTIES

GDS(L) lipases are interesting group of hydrolytic enzymes, often with multifunctional properties and potential for use in biotechnology. A putative lipase gene from Streptomyces coelicolor showed high amino acid sequence homology (66%) with cloned and characterised GDS(L) lipase from Streptomyces rimosus. The DNA fragment with lipase gene and ribosomal binding site (RBS) was PCR-amplified. In addition to six histidine codons at the 3’ terminus the primers contained convinient restriction sites for subsequent cloning. Amplifed DNA fragment was ligated into the pET-15b vector, resequenced and further subcloned into Streptomyces expression plasmid pANT849. This construct was transformed into heterologous, lipase defficient host Streptomyces lividans. Recombinant plasmid was purified, confirmed by PCR and transformant expressing the lipase protein was cultivated in the liquid medium. The time-course of lipase production in supernatant was monitored spectrofotometrically by following degradation of p-nitrophenyl palmitate and the cultivation was stopped after the increase of lipase activity ceased. A simple three step protein purification procedure was developed. Firstly, ammonium sulphate precipitation followed by Ni-NTA metal-affinity chromatography were applied. After elution protein sample contained approximately 80 % of lipase and a contaminant protein of higher molecular mass without lipase activity. Gel-filtration was applied as a final purification step yielding about 95 % of purified lipase. Basic biochemical features of the enzyme were determined and will be disscused in this study.

GDS(L) lipase activity; Streptomyces coelicolor

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