School of Biosciences, University of Sheffieldgrid.11835.3e, Sheffield, United Kingdom.
The Florey Institute for Host-Pathogen Interactions, University of Sheffieldgrid.11835.3e, Sheffield, United Kingdom.
mBio. 2022 Aug 30;13(4):e0066922. doi: 10.1128/mbio.00669-22. Epub 2022 Jun 15.
Bacterial cell division is a complex process requiring the coordination of multiple components to allow the appropriate spatial and temporal control of septum formation and cell scission. Peptidoglycan (PG) is the major structural component of the septum, and our recent studies in the human pathogen Staphylococcus aureus have revealed a complex, multistage PG architecture that develops during septation. Penicillin-binding proteins (PBPs) are essential for the final steps of PG biosynthesis; their transpeptidase activity links the peptide side chains of nascent glycan strands. PBP1 is required for cell division in S. aureus, and here, we demonstrate that it has multiple essential functions associated with its enzymatic activity and as a regulator of division. Loss of PBP1, or just its C-terminal PASTA domains, results in cessation of division at the point of septal plate formation. The PASTA domains can bind PG and thereby potentially coordinate the cell division process. The transpeptidase activity of PBP1 is also essential, but its loss leads to a strikingly different phenotype of thickened and aberrant septa, which is phenocopied by the morphological effects of adding the PBP1-specific β-lactam, meropenem. Together, these results lead to a model for septal PG synthesis where PBP1 enzyme activity is required for the characteristic architecture of the septum and PBP1 protein molecules enable the formation of the septal plate. Bacterial cell wall peptidoglycan is essential, and its synthesis is the target of clinically important antibiotics such as β-lactams. β-lactams target penicillin-binding proteins (PBPs) that assemble new peptidoglycan from its building blocks. The human pathogen Staphylococcus aureus only has two essential PBPs that can carry out all the functions necessary for growth and division. In the absence of the confounding antibiotic resistance-associated PBP PBP2A, PBP1 is required for cell division, and here, we have found that it has several essential functions, both as an enzyme and as a coordinator by binding to cell division proteins and to its peptidoglycan product, via its PASTA domains. This has led to a new model for cell division with PBP1 responsible for the synthesis of the characteristic architectural features of the septum.
细菌细胞分裂是一个复杂的过程，需要多个组件的协调，以实现隔膜形成和细胞分裂的适当空间和时间控制。肽聚糖（PG）是隔膜的主要结构成分，我们最近在人类病原体金黄色葡萄球菌中的研究揭示了一个复杂的、多阶段的 PG 结构，它在隔膜形成过程中发展。青霉素结合蛋白（PBPs）是 PG 生物合成最后步骤所必需的；它们的转肽酶活性将新生糖链的肽侧链连接起来。PBP1 是金黄色葡萄球菌细胞分裂所必需的，在这里，我们证明它具有与其酶活性相关的多个必需功能，以及作为分裂调节剂的功能。PBP1 的缺失，或仅其 C 端 PASTA 结构域的缺失，会导致在隔膜板形成点停止分裂。PASTA 结构域可以结合 PG，从而可能协调细胞分裂过程。PBP1 的转肽酶活性也是必需的，但它的缺失会导致明显不同的增厚和异常隔膜表型，这可以通过添加 PBP1 特异性β-内酰胺类药物美罗培南的形态学影响来模拟。这些结果共同导致了一个隔膜 PG 合成的模型，其中 PBP1 酶活性是隔膜特征结构所必需的，而 PBP1 蛋白分子则使隔膜板的形成成为可能。细菌细胞壁肽聚糖是必需的，其合成是临床重要抗生素（如β-内酰胺类抗生素）的靶点。β-内酰胺类抗生素靶向青霉素结合蛋白（PBPs），这些蛋白将新的肽聚糖从其构建块组装起来。人类病原体金黄色葡萄球菌只有两个必需的 PBPs，可以执行生长和分裂所必需的所有功能。在没有与抗生素耐药性相关的 PBP PBP2A 的情况下，PBP1 是细胞分裂所必需的，在这里，我们发现它具有几个必需的功能，既是一种酶，又是一种通过其 PASTA 结构域与细胞分裂蛋白和其肽聚糖产物结合的协调者。这导致了一个新的细胞分裂模型，其中 PBP1 负责隔膜特征结构的合成。
