title: Extracellular location of Thermobifida fusca cutinase expressed in Escherichia coli BL21(DE3) without mediation of a signal peptide.
abstract: Cutinase is a multifunctional esterase with potential industrial applications. In the present study, a truncated version of the extracellular Thermobifida fusca cutinase without a signal peptide (referred to as cutinase(NS)) was heterologously expressed in Escherichia coli BL21(DE3). The results showed that the majority of the cutinase activity was located in the culture medium. In a 3-liter fermentor, the cutinase activity in the culture medium reached 1,063.5 U/ml (2,380.8 mg/liter), and the productivity was 40.9 U/ml/h. Biochemical characterization of the purified cutinase(NS) showed that it has enzymatic properties similar to those of the wild-type enzyme. In addition, E. coli cells producing inactive cutinase(NS)S130A were constructed, and it was found that the majority of the inactive enzyme was located in the cytoplasm. Furthermore, T. fusca cutinase was confirmed to have hydrolytic activity toward phospholipids, an important component of the cell membrane. Compared to the cells expressing the inactive cutinase(NS)S130A, the cells expressing cutinase(NS) showed increased membrane permeability and irregular morphology. Based on these results, a hypothesis of "cell leakage induced by the limited phospholipid hydrolysis of cutinase(NS)" was proposed to explain the underlying mechanism for the extracellular release of cutinase(NS).
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.
authors.forename: Lingqia
authors.initials: L
authors.lastname: Su
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Woodard
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
mesh_terms: D000192:Actinomycetales / Q000201:enzymology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D002265:Carboxylic Ester Hydrolases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D003470:Culture Media / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005822:Genetic Vectors; D046529:Microscopy, Electron, Transmission; D021382:Protein Sorting Signals; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D055571:Secretory Pathway; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D002265:Carboxylic Ester Hydrolases; C019952:cutinase