Naslov
The SGNH-hydrolase of Streptomyces coelicolor has (aryl)esterase and a true lipase activity.

Autori
Bielen, Ana ; Ćetković, Helena ; Long, Paul F. ; Schwab, Helmuth ; Abramić, Marija ; Vujaklija, Dušica

Izvornik
Biochimie (0300-9084) 91 (2009), 3; 390-400

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Streptomyces coelicolor ; GDSL/SGNH porodica ; Lipaza ; (Aril)esteraza

Sažetak
The Streptomyces coelicolor A3(2) gene SCI11.14c was overexpressed and purified as a His-tagged protein from heterologous host, Streptomyces lividans. The purification procedure resulted in 34.1-fold increase in specific activity with an overall yield of 21.4%. Biochemical and physical properties of the purified enzyme were investigated and it was shown that it possesses (aryl)esterase and a true lipase activity. The enzyme was able to hydrolyze p-nitrophenyl-, alpha- and beta-naphthyl esters and poly(oxyethylene) sorbitan monoesters (Tween 20-80). It showed pronounced activity towards p-nitrophenyl and alpha- and beta-naphthyl esters of C(12)-C(16). Higher activity was observed with alpha-naphthyl esters. The enzyme hydrolyzed triolein (specific activity: 91.9U/mg) and a wide range of oils with a preference for those having higher content of linoleic or oleic acid (C18:2 ; C18:1, cis). The active-site serine specific inhibitor 3, 4-dichloroisocoumarin (DCI) strongly inhibited the enzyme, while tetrahydrofurane and 1, 4-dioxane significantly increased (2- and 4- fold, respectively) hydrolytic activity of lipase towards p-nitrophenyl caprylate. The enzyme exhibited relatively high temperature optimum (55 degrees C) and thermal stability. CD analysis revealed predominance of alpha-helical structure (54% alpha-helix, 21% beta-sheet) and a T(m) value at 66 degrees C. Systematic bioinformatic analysis of deduced amino acid sequence of S. coelicolor enzyme placed it to the SGNH-hydrolase family. Phylogenetic analysis of the predicted protein homologues to the S. coelicolor SGNH-hydrolase generated three distinct groups consisting of proteins from Actinomycetales, Ascomycota and nematodes. At present it seems that these enzymes are most conserved among soil inhabiting organisms.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Biologija

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