Armbruster Krista M, Jiang Jiawen, Sartorio Mariana G, Scott Nichollas E, Peterson Jenna M, Sexton Jonathan Z, Feldman Mario F, Koropatkin Nicole M
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA.
bioRxiv. 2024 Jun 1:2024.05.31.596883. doi: 10.1101/2024.05.31.596883.
Members of the Bacteroidota compose a large portion of the human gut microbiota, contributing to overall gut health via the degradation of various polysaccharides. This process is facilitated by lipoproteins, globular proteins anchored to the cell surface by a lipidated N-terminal cysteine. Despite their importance, lipoprotein synthesis by these bacteria is understudied. In , the α-amino linked lipid of lipoproteins is added by the lipoprotein -acyltransferase Lnt. Herein, we have identified a protein distinct from Lnt responsible for the same process in , named lipoprotein -acyltransferase in (Lnb). Deletion of Lnb yields cells that synthesize diacylated lipoproteins, with impacts on cell viability and morphology, growth on polysaccharides, and protein composition of membranes and outer membrane vesicles (OMVs). Our results not only challenge the accepted paradigms of lipoprotein biosynthesis in Gram-negative bacteria, but also support the establishment of a new family of lipoprotein -acyltransferases.
拟杆菌门的成员构成了人类肠道微生物群的很大一部分，通过降解各种多糖对整体肠道健康做出贡献。这个过程由脂蛋白促进，脂蛋白是通过脂化的N端半胱氨酸锚定在细胞表面的球状蛋白质。尽管它们很重要，但这些细菌的脂蛋白合成却研究不足。在[具体细菌名称]中，脂蛋白的α-氨基连接脂质由脂蛋白酰基转移酶Lnt添加。在此，我们鉴定出一种不同于Lnt的蛋白质，它在[具体细菌名称]中负责相同的过程，命名为[具体细菌名称]脂蛋白酰基转移酶（Lnb）。Lnb的缺失产生合成二酰化脂蛋白的细胞，对细胞活力和形态、多糖上的生长以及膜和外膜囊泡（OMV）的蛋白质组成有影响。我们的结果不仅挑战了革兰氏阴性菌中脂蛋白生物合成的公认范式，也支持了一个新的脂蛋白酰基转移酶家族的建立。
