Jiangsu Collaborative Innovation Centre for Regional Modern Agriculture and Environmental Protection, School of Life Science, Huaiyin Normal University, Huai'an 223300, China.
School of Agriculture, Food and Wine & Waite Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia.
Int J Mol Sci. 2022 Jan 31;23(3):1656. doi: 10.3390/ijms23031656.
Plant xyloglucan:xyloglucosyl transferases, known as xyloglucan endo-transglycosylases (XETs) are the key players that underlie plant cell wall dynamics and mechanics. These fundamental roles are central for the assembly and modifications of cell walls during embryogenesis, vegetative and reproductive growth, and adaptations to living environments under biotic and abiotic (environmental) stresses. XET enzymes (EC 2.4.1.207) have the β-sandwich architecture and the β-jelly-roll topology, and are classified in the glycoside hydrolase family 16 based on their evolutionary history. XET enzymes catalyse transglycosylation reactions with xyloglucan (XG)-derived and other than XG-derived donors and acceptors, and this poly-specificity originates from the structural plasticity and evolutionary diversification that has evolved through expansion and duplication. In phyletic groups, XETs form the gene families that are differentially expressed in organs and tissues in time- and space-dependent manners, and in response to environmental conditions. Here, we examine higher plant XET enzymes and dissect how their exclusively carbohydrate-linked transglycosylation catalytic function inter-connects complex plant cell wall components. Further, we discuss progress in technologies that advance the knowledge of plant cell walls and how this knowledge defines the roles of XETs. We construe that the broad specificity of the plant XETs underscores their roles in continuous cell wall restructuring and re-modelling.
木葡聚糖糖基转移酶，又称木葡聚糖内切糖基转移酶（XETs），是植物细胞壁动态和力学的关键调控因子。这些基本功能对于胚胎发生、营养和生殖生长过程中细胞壁的组装和修饰，以及生物和非生物（环境）胁迫下适应生活环境至关重要。XET 酶（EC 2.4.1.207）具有 β-三明治结构和 β-果冻卷拓扑结构，根据其进化历史，被归类为糖苷水解酶家族 16。XET 酶催化木葡聚糖（XG）衍生和非 XG 衍生供体和受体的转糖基化反应，这种多特异性源于结构可塑性和进化多样化，这是通过扩张和重复进化而来的。在系统发育群体中，XET 形成在器官和组织中以时间和空间依赖的方式以及响应环境条件差异表达的基因家族。在这里，我们研究高等植物 XET 酶，并剖析它们独特的碳水化合物连接的转糖基化催化功能如何相互连接复杂的植物细胞壁成分。此外，我们还讨论了推进植物细胞壁知识的技术进展，以及这些知识如何定义 XET 的作用。我们认为，植物 XET 的广泛特异性强调了它们在连续的细胞壁重构和重塑中的作用。
