A central role for PBP2 in the activation of peptidoglycan polymerization by the bacterial cell elongation machinery.
A central role for PBP2 in the activation of peptidoglycan polymerization by the bacterial cell elongation machinery.
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DOI：
10.1371/journal.pgen.1007726
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发表时间：
2018-10
期刊：
影响因子：
4.5
通讯作者：
Bernhardt TG
中科院分区：
文献类型：
--
作者：
Rohs PDA;Buss J;Sim SI;Squyres GR;Srisuknimit V;Smith M;Cho H;Sjodt M;Kruse AC;Garner EC;Walker S;Kahne DE;Bernhardt TG
棒状细菌中的细胞伸长由Rod系统介导，Rod系统是一种保守的形态发生复合体，通过聚糖聚合酶RodA和交联酶PBP 2在空间上控制细胞壁组装。使用大肠杆菌作为模型系统，我们确定了PBP 2的变体，促进杆系统功能时，必不可少的附属组件的机器失活。这种PBP 2变体在体内过度激活细胞壁合成，并在体外刺激RodA-PBP 2复合物的活性。细胞与活化的合成酶也表现出增强的肌动蛋白样MreB的杆系统的组件的聚合。我们的研究结果定义了一个激活途径，其中PBP 2构象在刺激其伴侣RodA的聚糖聚合和MreB的细胞骨架丝的形成以定向细胞壁组装中起着核心作用。根据这些结果，先前分离的激活胞质分裂的突变表明类似的途径也可能通过分裂机制控制细胞壁合成。细菌的细胞壁决定了它们的形状，并保护它们免受渗透溶解。细胞壁合成需要两种酶活性：聚糖聚合和交联。最近发现了一个主要的新的聚糖聚合酶家族，并提出与称为青霉素结合蛋白（PBP）的交联酶复合工作。这些酶的活性如何协调以防止未交联聚糖的毒性产生仍然是未知的。我们对大肠杆菌细胞延伸系统的分析表明，这种偶联是由PBP的变化介导的，PBP的变化激活了聚合酶的聚糖链合成。此外，我们目前的遗传证据表明，这一激活事件是由一个组件的伸长机械与以前未知的功能。这种激活途径的发现为细胞壁生物发生过程提供了新的机制见解，并确定了一种新的途径来破坏它用于抗生素开发。
Cell elongation in rod-shaped bacteria is mediated by the Rod system, a conserved morphogenic complex that spatially controls cell wall assembly by the glycan polymerase RodA and crosslinking enzyme PBP2. Using Escherichia coli as a model system, we identified a PBP2 variant that promotes Rod system function when essential accessory components of the machinery are inactivated. This PBP2 variant hyperactivates cell wall synthesis in vivo and stimulates the activity of RodA-PBP2 complexes in vitro. Cells with the activated synthase also exhibited enhanced polymerization of the actin-like MreB component of the Rod system. Our results define an activation pathway governing Rod system function in which PBP2 conformation plays a central role in stimulating both glycan polymerization by its partner RodA and the formation of cytoskeletal filaments of MreB to orient cell wall assembly. In light of these results, previously isolated mutations that activate cytokinesis suggest that an analogous pathway may also control cell wall synthesis by the division machinery. The cell wall of bacteria determines their shape and protects them from osmotic lysis. Two enzymatic activities are required for cell wall synthesis: glycan polymerization and crosslinking. A major new family of glycan polymerases was recently discovered and was proposed to work in complex with crosslinking enzymes called penicillin-binding proteins (PBPs). How the activities of these enzymes are coordinated to prevent the toxic generation of uncrosslinked glycans has remained unknown. Our analysis of the cell elongation system of Escherichia coli has revealed that this coupling is mediated by changes in the PBP that activate glycan chain synthesis by the polymerase. Furthermore, we present genetic evidence that this activation event is mediated by a component of the elongation machinery with a previously unknown function. Discovery of this activation pathway provides new mechanistic insight into the cell wall biogenesis process and identifies a new avenue to disrupt it for antibiotic development.
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影响因子：
3.6
作者：
Buss JA;Peters NT;Xiao J;Bernhardt TG
通讯作者：
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3.6
作者：
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影响因子：
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