Recombinant expression and characterisation of a lipase from the Antarctic zooplanktonSalpa thompsoni

Abstract

AbstractCold marine environments are abundant on earth and represent a rich resource for low temperature enzymes. Here we applyin silicobioprospecting methods followed byin vitroexpression and biochemical analyses to characterise a novel low temperature lipase from the Antarctic tunicateSalpa thompsoni. A 586 amino acid pancreatic lipase-like gene was identified fromS. thompsonitranscriptomic data, expressed as a hexahistadine fusion protein inEscherichia coliat 10°C and purified by affinity chromatography. Hydrolysis of the synthetic substrate ρ-nitrophenyl butyrate (PNPB) showed that this recombinant protein has optimal activity at 20 °C and pH 7, and a specific activity of 3.16 U/mg under this condition. Over 60% of enzyme activity was maintained between 15 to 25 °C, with a sharp decrease outside this range. These results are indicative of cold active psychrophilic enzyme activity. A meta-analysis of lipase activities towards PNPB showed that the novelS. thompsonilipase displays a higher activity at lower temperatures relative to previously characterised enzymes. The work demonstrates a methodology for conversion of transcriptomic toin vitroexpression data for the discovery of new cold-active biocatalysts from marine organisms.