Research Unit in Biology of Microorganisms (URBM), Narilis, University of Namur (UNamur), 61 rue de Bruxelles, 5000, Namur, Belgium.
Université de Poitiers, IC2MP, UMR CNRS 7285, Equipe "OrgaSynth", Groupe Glycochimie, 4 rue Michel Brunet, 86073, Poitiers, France.
Nat Commun. 2023 Feb 17;14(1):911. doi: 10.1038/s41467-023-36442-y.
Lipopolysaccharide is essential for most Gram-negative bacteria as it is a main component of the outer membrane. In the pathogen Brucella abortus, smooth lipopolysaccharide containing the O-antigen is required for virulence. Being part of the Rhizobiales, Brucella spp. display unipolar growth and lipopolysaccharide was shown to be incorporated at the active growth sites, i.e. the new pole and the division site. By localizing proteins involved in the lipopolysaccharide transport across the cell envelope, from the inner to the outer membrane, we show that the lipopolysaccharide incorporation sites are determined by the inner membrane complex of the lipopolysaccharide transport system. Moreover, we identify the main O-antigen ligase of Brucella spp. involved in smooth lipopolysaccharide synthesis. Altogether, our data highlight a layer of spatiotemporal organization of the lipopolysaccharide biosynthesis pathway and identify an original class of bifunctional O-antigen ligases.
脂多糖是大多数革兰氏阴性菌的必需成分，因为它是外膜的主要组成部分。在病原体布鲁氏菌中，含有 O 抗原的光滑脂多糖是毒力所必需的。作为根瘤菌科的一部分，布鲁氏菌属表现出单极生长，脂多糖被整合到活性生长部位，即新的极和分裂部位。通过定位参与脂多糖跨细胞膜运输的蛋白质，从内膜到外膜，我们表明脂多糖的掺入部位由脂多糖运输系统的内膜复合物决定。此外，我们鉴定了参与光滑脂多糖合成的布鲁氏菌属的主要 O 抗原连接酶。总之，我们的数据突出了脂多糖生物合成途径的时空组织的一个层次，并鉴定了一类原始的双功能 O 抗原连接酶。
