title: Characterization of antifungal chitinase from marine Streptomyces sp. DA11 associated with South China Sea sponge Craniella australiensis.
abstract: The gene cloning, purification, properties, kinetics, and antifungal activity of chitinase from marine Streptomyces sp. DA11 associated with South China sponge Craniella australiensis were investigated. Alignment analysis of the amino acid sequence deduced from the cloned conserved 451 bp DNA sequence shows the chitinase belongs to ChiC type with 80% similarity to chitinase C precursor from Streptomyces peucetius. Through purification by 80% ammonium sulfate, affinity binding to chitin and diethylaminoethyl-cellulose anion-exchange chromatography, 6.15-fold total purification with a specific activity of 2.95 Umg(-1) was achieved. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed a molecular weight of approximately 34 kDa and antifungal activities were observed against Aspergillus niger and Candida albicans. The optimal pH, temperature, and salinity for chitinase activity were 8.0, 50 degrees C, and 45 g per thousand psu, respectively, which may contribute to special application of this marine microbe-derived chitinase compared with terrestrial chitinases. The chitinase activity was increased by Mn(2+), Cu(2+), and Mg(2+), while strongly inhibited by Fe(2+) and Ba(2+). Meanwhile, SDS, ethyleneglycoltetraacetic acid, urea, and ethylenediaminetetraacetic acid were found to have significantly inhibitory effect on chitinase activity. With colloidal chitin as substrates instead of powder chitin, higher V (max) (0.82 mg product/min.mg protein) and lower K (m) (0.019 mg/ml) values were achieved. The sponge's microbial symbiont with chitinase activity may contribute to chitin degradation and antifungal defense. To our knowledge, it was the first time to study sponge-associated microbial chitinase.
authors.affiliation: Laboratory of Marine Biotechnology, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Han
authors.forename: Bingjie
authors.initials: B
authors.lastname: Yang
authors.forename: Fengli
authors.initials: F
authors.lastname: Zhang
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Miao
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000935:Antifungal Agents / Q000378:metabolism* / Q000494:pharmacology*; D002688:Chitinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D004789:Enzyme Activation; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D011161:Porifera / Q000382:microbiology*; D012965:Sodium Chloride; D013302:Streptomyces / Q000201:enzymology*; D013696:Temperature
chemical_list: D000935:Antifungal Agents; D012965:Sodium Chloride; D002688:Chitinases