Laboratory of Yeast Biology and Fermentation Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, 530007, China.
Department of Food Science, School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, 255000, China.
Protein Expr Purif. 2023 Nov;211:106343. doi: 10.1016/j.pep.2023.106343. Epub 2023 Aug 2.
As one of the major components in the fungal cell wall, chitin is a polymer of β-1,4-linked N-acetylglucosamine. Chitinases are hydrolytic enzymes that break down glycosidic bonds in the chitin. The human fungal pathogen Candida albicans has three chitinase-encoding genes, CaCHT1, CaCHT2 and CaCHT3. The CaCHT4 gene encodes a protein with the glycoside hydrolase family GH18 domain, Glyco_18, which suggests that CaCht4 might be a chitinase. In the present study, we have cloned, expressed and purified the N-terminally His6-tagged CaCht4 protein from bacterial cells. Further biochemical characterization has shown that this recombinant CaCht4 protein shows both exochitinase (chitobiosidase) and endochitinase activities, but has no N-acetylglucosaminase activity. The optimal temperature for the exochitinase activity of CaCht4 is 55 °C. Taken together, these data support that the CaCHT4 gene encodes a chitinase. Our finding provides a basis for us to understand the biological functions of the CaCHT4 gene in C. albicans.
作为真菌细胞壁的主要成分之一，几丁质是一种β-1,4 连接的 N-乙酰葡萄糖胺聚合物。几丁质酶是水解酶，可分解几丁质中的糖苷键。人类真菌病原体白色念珠菌有三个几丁质酶编码基因，CaCHT1、CaCHT2 和 CaCHT3。CaCHT4 基因编码一种具有糖苷水解酶家族 GH18 结构域 Glyco_18 的蛋白质，这表明 CaCht4 可能是一种几丁质酶。在本研究中，我们从细菌细胞中克隆、表达和纯化了 N 端 His6 标记的 CaCht4 蛋白。进一步的生化特性表明，这种重组 CaCht4 蛋白具有外切几丁质酶（壳二糖酶）和内切几丁质酶活性，但没有 N-乙酰氨基葡萄糖酶活性。CaCht4 外切几丁质酶活性的最佳温度为 55°C。综上所述，这些数据支持 CaCHT4 基因编码一种几丁质酶。我们的发现为我们理解 CaCHT4 基因在白色念珠菌中的生物学功能提供了基础。
