Waheed Abdul, Chen Yi, Su Ying, Yan Yuxin, Liu Gang
Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
J Fungi (Basel). 2025 Mar 25;11(4):250. doi: 10.3390/jof11040250.
Xylanases are crucial for the breakdown of hemicellulose, enabling the conversion of lignocellulosic biomass into fermentable sugars for biofuels and other industrial applications. For the first time, we investigated the biochemical and genetic characteristics of 22 xylanase genes from within glycoside hydrolase (GH) families GH10, GH11, and GH43. Xylanase genes structural diversity clustered the phylogenetic tree into GH10, GH11, GH43-I, and GH43-II groups. Structural analysis revealed that all and genes contained conserved GH domains, with CBM1 present in and . Secondary domains, including CBM35, CBM42, and CBM91, were found in the GH43 gene family. The presence of key glutamic (Glu) and aspartic (Asp) residues in active sites is essential for substrate binding and catalysis. RT-qPCR analysis revealed substrate-dependent gene expression, with peak upregulation on day three in beechwood xylan (BWX) cultures and day two in corncob xylan (CCX) and rice straw (RS) cultures. Consistent with these findings, enzymatic assays demonstrated the highest xylanase activity in BWX-induced cultures, followed by RS and CCX, underscoring the differential regulation of these enzymes in response to distinct hemicellulosic substrates. These findings provide valuable insights into the structural, functional, and regulatory mechanisms of xylanases, facilitating their industrial application.
木聚糖酶对于半纤维素的分解至关重要，能够将木质纤维素生物质转化为可发酵糖，用于生物燃料和其他工业应用。我们首次研究了糖苷水解酶（GH）家族GH10、GH11和GH43中22个木聚糖酶基因的生化和遗传特征。木聚糖酶基因的结构多样性将系统发育树聚类为GH10、GH11、GH43-I和GH43-II组。结构分析表明，所有基因都含有保守的GH结构域，其中基因含有CBM1结构域。在GH43基因家族中发现了包括CBM35、CBM42和CBM91在内的二级结构域。活性位点中关键的谷氨酸（Glu）和天冬氨酸（Asp）残基的存在对于底物结合和催化至关重要。RT-qPCR分析揭示了底物依赖性基因表达，在山毛榉木聚糖（BWX）培养物中第三天、玉米芯木聚糖（CCX）和稻草（RS）培养物中第二天出现上调峰值。与这些发现一致，酶活性测定表明BWX诱导培养物中的木聚糖酶活性最高，其次是RS和CCX，这突出了这些酶对不同半纤维素底物的差异调节。这些发现为木聚糖酶的结构、功能和调节机制提供了有价值的见解，促进了它们的工业应用。
