An altered FtsA can compensate for the loss of essential cell division protein FtsN in Escherichia coli
An altered FtsA can compensate for the loss of essential cell division protein FtsN in Escherichia coli
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DOI：
10.1111/j.1365-2958.2007.05738.x
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发表时间：
2007-06-01
影响因子：
3.6
通讯作者：
Margolin, William
中科院分区：
文献类型：
--
作者：
Bernard, Christophe S.;Sadasivam, Mahalakshmi;Margolin, William
FtsN是最后一个已知的被招募到大肠杆菌分裂体的必需蛋白质组分，并且具有几种特殊性质。在这里，我们报告的抑制突变体的ftsA，允许在没有ftsN的情况下的生存能力的分离。细胞产生的FtsA抑制剂表现出轻微的细胞分裂缺陷的FtsN的情况下，没有明显的表型在其存在。值得注意的是，这些改变的FtsA蛋白也可以部分抑制ftsK或zipA的缺失，当过量时毒性低于野生型FtsA，并赋予对过量MinC的抗性，表明它们与先前分离的FtsA* 抑制突变体共享一些特性，并通过增加Z环的完整性绕过对ftsN的需要。托拉，这通常需要FtsN为它的招聘分裂体，本地化熟练的抑制ftsN空菌株，强烈表明，FtsN不招募的Tol-tolN复合物直接。因此，尽管FtsN被分类为核心分裂组分，但它没有独特的基本功能，而是促进了整体Z环的完整性。结果强烈表明，FtsA是构象灵活的，这种灵活性是一个关键的调制器的divisome功能在所有阶段。
FtsN is the last known essential protein component to be recruited to the Escherichia coli divisome, and has several special properties. Here we report the isolation of suppressor mutants of ftsA that allow viability in the absence of ftsN. Cells producing the FtsA suppressors exhibited a mild cell division deficiency in the absence of FtsN, and no obvious phenotype in its presence. Remarkably, these altered FtsA proteins also could partially suppress a deletion of ftsK or zipA, were less toxic than wild-type FtsA when in excess, and conferred resistance to excess MinC, indicating that they share some properties with the previously isolated FtsA* suppressor mutant, and bypass the need for ftsN by increasing the integrity of the Z ring. TolA, which normally requires FtsN for its recruitment to the divisome, localized proficiently in the suppressed ftsN null strain, strongly suggesting that FtsN does not recruit the Tol-Pal complex directly. Therefore, despite its classification as a core divisome component, FtsN has no unique essential function but instead promotes overall Z ring integrity. The results strongly suggest that FtsA is conformationally flexible, and this flexibility is a key modulator of divisome function at all stages.