Zhang Wenhao, Qiu Zili, Zhao Qiuyun, Liu Ziyi, Zhang Xiaorong, Song Houhui, Xu Chenggang
College of Veterinary Medicine, Zhejiang A&F University, Hangzhou, Zhejiang, China.
Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Hangzhou, Zhejiang, China.
Appl Environ Microbiol. 2025 Jun 18;91(6):e0006225. doi: 10.1128/aem.00062-25. Epub 2025 May 30.
Xylan, a major component of hemicellulose, is crucially targeted by xylanases for its breakdown. This study focuses on the free xylanase XynB from to elucidate its expression and regulatory mechanisms. We successfully achieved heterologous expression and purification of recombinant XynB, verifying its enzymatic activity specifically against xylan. The mutation of confirmed its essential role in xylan degradation by . We further explored the transcription of under various carbon sources and uncovered its regulatory mechanisms mediated by two-component systems (TCSs). We found that transcription is activated by the xylan-sensing TCS (XuaDRS) and repressed by the cellobiose-sensing TCS (CuaDRS). This research enriches our understanding of the regulatory mechanisms governing the activity and expression of free xylanases like XynB from , offering potential targets for the genetic engineering and process optimization of cellulolysis.IMPORTANCE, an anaerobic, mesophilic, and cellulolytic gram-positive bacterium, is a model organism for the microbial degradation of plant cell wall polysaccharides and a promising host for biofuel production from lignocelluloses. The degradation process of lignocellulosic materials is complex due to their intricate structure and interlocking complexity. XynB, a GH11 family xylanase, plays a significant role in the breakdown of xylan, a major constituent of hemicelluloses. Our study reveals the molecular mechanisms that link the specific adaptation of xylan utilization with the general stress response in the regulatory network of , particularly by detailing the synergistic effects of two two-component systems on the transcriptional regulation of . This knowledge is essential for harnessing the full potential of in the production of biofuels from lignocellulosic biomass.
木聚糖是半纤维素的主要成分，木聚糖酶主要作用于木聚糖以将其分解。本研究聚焦于[具体来源]的游离木聚糖酶XynB，以阐明其表达和调控机制。我们成功实现了重组XynB的异源表达和纯化，验证了其对木聚糖具有特异性的酶活性。[具体位点]的突变证实了其在[具体菌株]木聚糖降解中的关键作用。我们进一步探究了[具体基因]在各种碳源下的转录情况，并揭示了由双组分系统（TCSs）介导的调控机制。我们发现[具体基因]的转录受到木聚糖感应TCS（XuaDRS）的激活，并受到纤维二糖感应TCS（CuaDRS）的抑制。本研究丰富了我们对[具体来源]中如XynB这类游离木聚糖酶活性和表达调控机制的理解，为纤维素分解的基因工程和工艺优化提供了潜在靶点。重要性：[具体菌株]是一种厌氧、嗜温且具有纤维素分解能力的革兰氏阳性菌，是植物细胞壁多糖微生物降解的模式生物，也是从木质纤维素生产生物燃料的有前景的宿主。由于木质纤维素材料结构复杂且相互交错，其降解过程很复杂。XynB是一种GH11家族木聚糖酶，在木聚糖（半纤维素的主要成分）分解中起重要作用。我们的研究揭示了在[具体菌株]调控网络中，将木聚糖利用的特定适应性与一般应激反应联系起来的分子机制，特别是详细阐述了两个双组分系统对[具体基因]转录调控的协同作用。这些知识对于充分发挥[具体菌株]在从木质纤维素生物质生产生物燃料方面的潜力至关重要。
