College of Life Science, Sichuan Normal University, Chengdu, 610101, China.
Sichuan Vocational and Technical College, Suining, 629000, China.
Protein Expr Purif. 2024 Nov;223:106562. doi: 10.1016/j.pep.2024.106562. Epub 2024 Jul 31.
Previous studies have demonstrated the presence of chitinase in Bacillus velezensis through extensive genomic sequencing and experimental analyses. However, the detailed structure, functional roles, and antifungal activity of these chitinases remain poorly characterized. In this study, genomic screening identified three genes-chiA, chiB, and lpmo10-associated with chitinase degradation in B. velezensis S161. These genes encode chitinases ChiA and ChiB, and lytic polysaccharide monooxygenase LPMO10. Both ChiA and ChiB contain two CBM50 binding domains and one catalytic domain, whereas LPMO10 includes a signal peptide and a single catalytic domain. The chitinases ChiA, its truncated variant ChiA2, and ChiB were heterologously expressed in Escherichia coli. The purified enzymes efficiently degraded colloidal chitin and inhibited the spore germination of Penicillium digitatum. Notably, even after losing one CBM50 domain, the resultant enzyme, consisting of the remaining CBM50 domain and the catalytic domain, maintained its colloidal chitin hydrolysis and antifungal activity, indicating commendable stability. These results underscore the role of B. velezensis chitinases in suppressing plant pathogenic fungi and provide a solid foundation for developing and applying chitinase-based biocontrol strategies.
先前的研究通过广泛的基因组测序和实验分析表明，解淀粉芽孢杆菌中存在几丁质酶。然而，这些几丁质酶的详细结构、功能作用和抗真菌活性仍未得到很好的描述。在这项研究中，通过基因组筛选鉴定出与解淀粉芽孢杆菌 S161 中几丁质降解相关的三个基因——chiA、chiB 和 lpmo10。这些基因编码几丁质酶 ChiA 和 ChiB，以及溶菌多糖单加氧酶 LPMO10。ChiA 和 ChiB 均包含两个 CBM50 结合结构域和一个催化结构域，而 LPMO10 则包含一个信号肽和一个单一的催化结构域。几丁质酶 ChiA、其截断变体 ChiA2 和 ChiB 在大肠杆菌中进行了异源表达。纯化后的酶能有效降解胶体几丁质并抑制柑橘青霉孢子的萌发。值得注意的是，即使失去一个 CBM50 结构域，由剩余的 CBM50 结构域和催化结构域组成的酶仍然保持其胶体几丁质水解和抗真菌活性，表明其具有出色的稳定性。这些结果突出了解淀粉芽孢杆菌几丁质酶在抑制植物病原菌中的作用，并为开发和应用基于几丁质酶的生物防治策略提供了坚实的基础。
