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Abstract：
In this study, a novel strain for degrading chitin was identified as Bacillus paralicheniformis HL37, and the key chitinase CH1 was firstly mined through recombinant expression in Bacillus amyloliquefaciens HZ12. Subsequently, the sequence composition and catalytic mechanism of CH1 protein were analyzed. The molecular docking indicated that the triplet of Asp526, Asp528, and Glu530 was a catalytic active center. The enzymatic properties analysis revealed that the optimal reaction temperature and pH was 65 °C and 6.0, respectively. Especially, the chitinase activity showed no significant change below 55 °C and it could maintain over 60% activity after exposure to 85 °C for 30 min. Moreover, the optimal host strain and signal peptide were obtained to enhance the expression of chitinase CH1 significantly. As far as we know, it was the first time finding the highly efficient chitin-degrading enzymes in B. paralicheniformis, and detailed explanations were provided on the catalytic mechanism and enzymatic properties on CH1.
摘要：
在这项研究中,鉴定出一株降解几丁质的新菌株为副衣芽孢杆菌HL37，并通过在解淀粉芽孢杆菌HZ12中重组表达，首次发现了关键的几丁质酶CH1。随后，分析了CH1蛋白的序列组成和催化机理。分子对接表明Asp526、Asp528和Glu530的三重态是催化活性中心。酶学性质分析表明，最佳反应温度和pH分别为65°C和6.0。尤其是,低于55°C时几丁质酶活性无明显变化，暴露于85°C30分钟后可保持60％以上的活性。此外，获得了能显著增强几丁质酶CH1表达的最佳宿主菌株和信号肽。据我们所知,这是在副显形芽孢杆菌中首次发现高效的几丁质降解酶，并对CH1的催化机理和酶学性质进行了详细解释。
