engleski

Purification and characterization of the GDS(L) lipases from streptomycetes

An interesting subclass of lipolytic enzymes that possesses a distinct GDSL sequence motif has multifunctional properties with potential for use in the hydrolysis and synthesis of important ester compounds of biotechnological interests. The sequencing of the genomes of several streptomycete species revealed that these bacteria have great potential for synthesis of a broad spectrum of lipases. In the last decade, our group has done intensive research on GDS(L) lipases from Streptomyces. Several genes encoding GDS(L) lipases have been cloned so far and the enzymes from S. rimosus (Q93MW7, SrL) and S. coelicolor (SCO1725, Sc1) were expressed and purified from heterologous and homologous host. Lipases were extensively biochemically characterized and the properties of these enzymes were compared. These enzymes might have significant biotechnological potential due to high working temperature ; stability in organic solvents, activity over a broad range of pH and temperature, and the ability to hydrolyze numerous classes of substrates. The most pronounced difference between SrL and Sc1 is in acyl chain length specificity, as SrL shows maximal activity toward substrates with chain lengths C8-C10, and Sc1 shows preference for substrates with longer acyl-chain lengths (C14). Further, enzymes are stable in several tested organic solvents, while some solvents even increase their activity (eg. dioxane). Although the structures of enzymes have not been solved, both enzymes are predominantly α-helical proteins, as shown by CD spectroscopy. The amino acid residues important for the catalytic activity were predicted, mutated and the activities of wild type enzyme and mutants were analyzed.

GDS(L) lipases; streptomycetes

nije evidentirano