Morimoto Kenji, Yoshimoto Michiko, Karita Shuichi, Kimura Tetsuya, Ohmiya Kunio, Sakka Kazuo
Rare Sugar Research Center, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0795, Japan.
Appl Microbiol Biotechnol. 2007 Jan;73(5):1106-13. doi: 10.1007/s00253-006-0582-4. Epub 2006 Nov 8.
A novel chitinase gene chiC of Clostridium paraputrificum M-21, a chitinolytic and hydrogen-gas-producing bacterium, was characterized along with its translated product. The chi18C gene encodes 683 amino acids (signal peptide included) with a deduced molecular weight of 74,651. Chi18C is a modular enzyme composed of a family-18 catalytic module of glycoside hydrolases, two reiterated modules of unknown function, and a family-12 carbohydrate-binding module. Recombinant Chi18C was active toward soluble and insoluble chitin preparations, and synthetic substrates such as 4-methylumbelliferyl-beta-D: -N-N'-N''-triacetylchitotriose, but not active toward 4-MU-N-acetylglucosamine or 4-MU-beta-D: -N-N'-diacetylchitobioside. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunological analyses suggested that the expression of chi18C was inducible with chitinous substrates and that Chi18C was secreted into the culture medium. A possible role of Chi18C in the chitinolytic system of C. paraputrificum M-21 is discussed.
对产氢解几丁质细菌副腐败梭菌M-21的一种新型几丁质酶基因chiC及其翻译产物进行了表征。chi18C基因编码683个氨基酸（包括信号肽），推导分子量为74,651。Chi18C是一种模块化酶，由糖苷水解酶的18家族催化模块、两个功能未知的重复模块和一个12家族碳水化合物结合模块组成。重组Chi18C对可溶性和不溶性几丁质制剂以及合成底物如4-甲基伞形酮基-β-D：-N-N'-N''-三乙酰壳三糖有活性，但对4-MU-N-乙酰葡糖胺或4-MU-β-D：-N-N'-二乙酰壳二糖无活性。十二烷基硫酸钠聚丙烯酰胺凝胶电泳和免疫分析表明，chi18C的表达可被几丁质底物诱导，且Chi18C分泌到培养基中。讨论了Chi18C在副腐败梭菌M-21几丁质分解系统中的可能作用。
