MinE conformational dynamics regulate membrane binding, MinD interaction, and Min oscillation
MinE conformational dynamics regulate membrane binding, MinD interaction, and Min oscillation
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DOI：
10.1073/pnas.1707385114
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发表时间：
2017-07-18
影响因子：
11.1
通讯作者：
Lutkenhaus, Joe
中科院分区：
文献类型：
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作者：
Park, Kyung-Tae;Villar, Maria T.;Lutkenhaus, Joe
在大肠杆菌中，MinE诱导MinC/MinD在细胞两端之间振荡，有助于将Z环精确地放置在细胞中间。为了做到这一点，MinE经历了一个显著的构象变化，从一个潜伏的β -链形式在细胞质中扩散到一个活跃的β -链形式结合到膜和MinD。这种构象转换是如何发生的尚不清楚。在这里，使用氢-氘交换耦合质谱（HDX-MS），我们排除了两种形式处于快速平衡的模型。此外，HDX-MS揭示了MinE突变体（D45A/V49A），先前显示产生异常振荡并且无法组装MinE环，比WT MinE更刚性。这个突变体在与MinD的相互作用上有缺陷，这表明它很难转换为主动形式。基因内抑制因子分析表明，该突变体难以释放n端膜靶向序列（MTS）。这些结果表明，MTS与β -薄片的动态关联是经过微调的，以平衡MinE在膜上感知MinD的需要和它在细胞质中扩散的需要，这两者都是振荡所必需的。结果建立了矿井活化和矿井环形成模型。
In Escherichia coli MinE induces MinC/MinD to oscillate between the ends of the cell, contributing to the precise placement of the Z ring at midcell. To do this, MinE undergoes a remarkable conformational change from a latent 6 beta-stranded form that diffuses in the cytoplasm to an active 4 beta-stranded form bound to the membrane and MinD. How this conformational switch occurs is not known. Here, using hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS) we rule out a model in which the two forms are in rapid equilibrium. Furthermore, HDX-MS revealed that a MinE mutant (D45A/V49A), previously shown to produce an aberrant oscillation and unable to assemble a MinE ring, is more rigid than WT MinE. This mutant has a defect in interaction with MinD, suggesting it has difficulty in switching to the active form. Analysis of intragenic suppressors of this mutant suggests it has difficulty in releasing the N-terminal membrane targeting sequences (MTS). These results indicate that the dynamic association of the MTS with the beta-sheet is fine-tuned to balance MinE's need to sense MinD on the membrane with its need to diffuse in the cytoplasm, both of which are necessary for the oscillation. The results lead to models for MinE activation and MinE ring formation.