SEDS-bPBP pairs direct lateral and septal peptidoglycan synthesis in Staphylococcus aureus
SEDS-bPBP pairs direct lateral and septal peptidoglycan synthesis in Staphylococcus aureus
复制标题
DOI：
10.1038/s41564-019-0437-2
复制
发表时间：
2019-08-01
影响因子：
28.3
通讯作者：
Pinho, Mariana G.
中科院分区：
文献类型：
--
作者：
Reichmann, Nathalie T.;Tavares, Andreia C.;Pinho, Mariana G.
肽聚糖(PGN)是细菌细胞壁的主要成分，这种结构对细胞的物理完整性和形状是必不可少的。细菌通过将PGN掺入细胞的不同区域，即通过定位晚期PGN合成蛋白来维持细胞形状。这些包括两个关键的蛋白质家族，SEDS转糖基酶和BPBP转肽酶，被认为在同源对中起作用。杆状细菌有两个SED-BPBP对，参与伸长和分裂。在这里，我们解释为什么球状细菌，如金黄色葡萄球菌，也具有两个SED-BPBP对。我们确定金黄色葡萄球菌RodA-PBP3和FtsW-PBP1可能构成相互作用的同源蛋白对。缺乏RodA-PBP3可导致侧壁PGN合成不足，从而导致更多的球状细胞，而FtsW-PBP1缺失则阻止正常的间隔PGN掺入。虽然PBP1是一种必需蛋白，但缺乏PBP1转肽酶活性的突变体是可行的，这表明该蛋白还有第二个功能。我们认为FtsW-PBP1对在中间细胞具有稳定分裂体的作用。在没有这些蛋白质的情况下，分裂体看起来像多个环或弧形，驱动侧向的PGN掺入，导致细胞延长。我们得出结论，RodA-PBP3和FtsW-PBP1分别介导侧壁和间隔PGN的掺入，并且它们的活性必须保持平衡以维持球状形态。
Peptidoglycan (PGN) is the major component of the bacterial cell wall, a structure that is essential for the physical integrity and shape of the cell. Bacteria maintain cell shape by directing PGN incorporation to distinct regions of the cell, namely, through the localization of late-stage PGN synthesis proteins. These include two key protein families, SEDS transglycosylases and bPBP transpeptidases, proposed to function in cognate pairs. Rod-shaped bacteria have two SEDS-bPBP pairs, involved in elongation and division. Here, we elucidate why coccoid bacteria, such as Staphylococcus aureus, also possess two SEDS-bPBP pairs. We determined that S. aureus RodA-PBP3 and FtsW-PBP1 probably constitute cognate pairs of interacting proteins. A lack of RodA-PBP3 resulted in more spherical cells due to deficient sidewall PGN synthesis, whereas depletion of FtsW-PBP1 arrested normal septal PGN incorporation. Although PBP1 is an essential protein, a mutant lacking PBP1 transpeptidase activity is viable, showing that this protein has a second function. We propose that the FtsW-PBP1 pair has a role in stabilizing the divisome at midcell. In the absence of these proteins, the divisome appears as multiple rings or arcs that drive lateral PGN incorporation, leading to cell elongation. We conclude that RodA-PBP3 and FtsW-PBP1 mediate sidewall and septal PGN incorporation, respectively, and that their activity must be balanced to maintain coccoid morphology.