Department of Biochemical Engineering, Graduate School of Sciences and Engineering, Yamagata University, Jonan, Yonezawa, Yamagata 992-8510, Japan.
Department of Biochemical Engineering, Graduate School of Sciences and Engineering, Yamagata University, Jonan, Yonezawa, Yamagata 992-8510, Japan.
J Biosci Bioeng. 2021 Apr;131(4):348-355. doi: 10.1016/j.jbiosc.2020.11.005. Epub 2020 Dec 3.
The chitin-assimilating gram-negative bacterium, Lysobacter sp. MK9-1, was isolated from soil and was the source of a glycoside hydrolase family 19-type chitinase (Chi19MK) gene that is 933-bp long and encodes a 311-residue protein. The deduced amino acid sequence of Chi19MK includes a signal peptide, an uncharacterized sequence, a carbohydrate-binding module family 12-type chitin binding domain, and a catalytic domain. The catalytic domain of Chi19MK is approximately 60% similar to those of ChiB from Burkholderia gladioli CHB101, chitinase N (ChiN) from Chitiniphilus shinanonensis SAY3, ChiF from Streptomyces coelicolor A3(2), Chi30 from Streptomyces olivaceoviridisis, ChiA from Streptomyces cyaneus SP-27, and ChiC from Streptomyces griseus HUT6037. Chi19MK lacking the signal and uncharacterized sequences (Chi19MKΔNTerm) was expressed in Escherichia coli Rosetta-gami B(DE3), resulting in significant chitinase activity in the soluble fraction. Purified Chi19MKΔNTerm hydrolyzed colloidal chitin and released disaccharide. Furthermore, Chi19MKΔNTerm inhibited hyphal extension in Trichoderma reesei and Schizophyllum commune. Based on quantitative antifungal activity assays, Chi19MKΔNTerm inhibits the growth of Trichoderma viride with an IC value of 0.81 μM.
从土壤中分离到一株能同化几丁质的革兰氏阴性细菌，命名为 Lysobacter sp. MK9-1，该菌是糖苷水解酶家族 19 型几丁质酶（Chi19MK）基因的来源，该基因长 933bp，编码一个 311 个氨基酸残基的蛋白质。Chi19MK 的推导氨基酸序列包括一个信号肽、一个未鉴定序列、一个碳水化合物结合模块家族 12 型几丁质结合域和一个催化结构域。Chi19MK 的催化结构域与 Burkholderia gladioli CHB101 中的 ChiB、Chitiniphilus shinanonensis SAY3 中的 ChiN、Streptomyces coelicolor A3(2)中的 ChiF、Streptomyces olivaceoviridisis 中的 Chi30、Streptomyces cyaneus SP-27 中的 ChiA 和 Streptomyces griseus HUT6037 中的 ChiC 的相似性约为 60%。在大肠杆菌 Rosetta-gami B(DE3)中表达缺失信号肽和未鉴定序列的 Chi19MK（Chi19MKΔNTerm），可使可溶性部分的几丁质酶活性显著增加。纯化的 Chi19MKΔNTerm 水解胶体几丁质并释放二糖。此外，Chi19MKΔNTerm 抑制了绿色木霉和裂褶菌的菌丝延伸。基于定量抗真菌活性测定，Chi19MKΔNTerm 对绿色木霉的生长抑制作用的 IC 值为 0.81μM。
