Discovery of a Diverse Set of Bacteria That Build Their Cell Walls without the Canonical Peptidoglycan Polymerase aPBP.
Discovery of a Diverse Set of Bacteria That Build Their Cell Walls without the Canonical Peptidoglycan Polymerase aPBP.
复制标题
DOI：
10.1128/mbio.01342-21
复制
发表时间：
2021-08-31
期刊：
影响因子：
6.4
通讯作者：
Salje J
中科院分区：
文献类型：
--
作者：
Atwal S;Chuenklin S;Bonder EM;Flores J;Gillespie JJ;Driscoll TP;Salje J
肽聚糖 (PG) 是一种高度交联的肽-聚糖网，赋予大多数细菌细胞结构刚性和形状。新 PG 的聚合通常是通过两种膜结合机制（A 类青霉素结合蛋白 (aPBP) 和 B 类青霉素结合蛋白 (bPBP) 与形状、伸长、分裂和孢子形成 (SEDS) 蛋白复合体）的协同活性来实现的。在这里，我们鉴定了四类在系统发育上不同的细菌，它们缺乏任何可识别的 aPBP。我们对这些组中的一组物种（立克次体目）进行了实验，发现缺乏 aPBP 的细菌构建了一种类似 PG 的细胞壁，相对于含有 aPBP 的细菌的细胞壁，其丰度和刚性最小。这种减少的细胞壁可能已经进化到最大限度地减少宿主对病原体和内共生体反应的激活，同时保留细胞伸长和分裂所需的最小PG生物合成机制。我们将这些细菌称为“肽聚糖中间体”细菌，这是一组与宿主相关的物种，其中包括一些人类病原体。
Peptidoglycan (PG) is a highly cross-linked peptide-glycan mesh that confers structural rigidity and shape to most bacterial cells. Polymerization of new PG is usually achieved by the concerted activity of two membrane-bound machineries, class-A penicillin binding proteins (aPBPs) and class-B penicillin binding proteins (bPBPs) in complex with shape, elongation, division, and sporulation (SEDS) proteins. Here, we have identified four phylogenetically distinct groups of bacteria that lack any identifiable aPBPs. We performed experiments on a panel of species within one of these groups, the Rickettsiales, and found that bacteria lacking aPBPs build a PG-like cell wall with minimal abundance and rigidity relative to cell walls of aPBP-containing bacteria. This reduced cell wall may have evolved to minimize the activation of host responses to pathogens and endosymbionts while retaining the minimal PG-biosynthesis machinery required for cell elongation and division. We term these “peptidoglycan-intermediate” bacteria, a cohort of host-associated species that includes some human pathogens.