A Thermostable Chitinase from the Antagonistic Chromobacterium violaceum that Inhibits the Development of Phytopathogenic Fungi

Publication date: Available online 1 April 2019Source: Enzyme and Microbial TechnologyAuthor(s): Antônio J.S. Sousa, Christiana F.B. Silva, Jeanlex S. Sousa, José E. Monteiro-Júnior, José E.C. Freire, Bruno L. Sousa, Marina D.P. Lobo, Ana C.O. Monteiro-Moreira, Thalles B. GrangeiroAbstractThe biocontrol activity of some soil strains of Chromobacterium sp. against pathogenic fungi has been attributed to secreted chitinases. The aim of this work was to characterize biochemically a recombinant chitinase (CvChi47) from C. violaceum ATCC 12472 and to investigate its effects on phytopathogenic fungi. CvChi47 is a modular enzyme with 450 amino acid residues, containing a type I signal peptide at the N-terminal region, followed by one catalytic domain belonging to family 18 of the glycoside hydrolases, and two type-3 chitin-binding domains at the C-terminal end. The recombinant enzyme was expressed in Escherichia coli as a His-tagged protein and purified to homogeneity. The native signal peptide of CvChi47 was used to direct its secretion into the culture medium, from where the recombinant product was purified by affinity chromatography on chitin and immobilized metal. The purified protein showed an apparent molecular mass of 46 kDa, as estimated by denaturing polyacrylamide gel electrophoresis, indicating the removal of the signal peptide. CvChi47 was a thermostable protein, retaining approximately 53.7% of its activity when heated at 100 °C for 1 h. The optimum hydrolyti...
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research