Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
Department of Biotechnology, School of Interdisciplinary and Applied Sciences, Central University of Haryana, Mahendragarh, Haryana, India.
Nat Commun. 2021 Jan 14;12(1):369. doi: 10.1038/s41467-020-20579-1.
Lipopolysaccharides are important components of the bacterial cell envelope that among other things act as a protective barrier against the environment and toxic molecules such as antibiotics. One of the most widely disseminated pathways of polysaccharide biosynthesis is the inner membrane bound Wzy-dependent pathway. Here we present the 3.0 Å structure of the co-polymerase component of this pathway, WzzB from E. coli solved by single-particle cryo-electron microscopy. The overall architecture is octameric and resembles a box jellyfish containing a large bell-shaped periplasmic domain with the 2-helix transmembrane domain from each protomer, positioned 32 Å apart, encircling a large empty transmembrane chamber. This structure also reveals the architecture of the transmembrane domain, including the location of key residues for the Wzz-family of proteins and the Wzy-dependent pathway present in many Gram-negative bacteria, explaining several of the previous biochemical and mutational studies and lays the foundation for future investigations.
脂多糖是细菌细胞包膜的重要组成部分，除其他功能外，它还充当抵御环境和抗生素等有毒分子的保护屏障。多糖生物合成的最广泛传播途径之一是内膜结合的 Wzy 依赖性途径。在这里，我们通过单颗粒冷冻电子显微镜解决了来自大肠杆菌的这种途径的共聚合酶成分 WzzB 的 3.0Å 结构。整体结构为八聚体，类似于箱形水母，包含一个大型钟形周质域，每个原聚体的 2 螺旋跨膜域，彼此相距 32Å，环绕着一个大型空跨膜腔。该结构还揭示了跨膜域的结构，包括 Wzz 家族蛋白的关键残基位置和许多革兰氏阴性菌中存在的 Wzy 依赖性途径，解释了之前的一些生化和突变研究，并为未来的研究奠定了基础。
