The Escherichia coli Min system plays an important role in the proper placement of the septum ring at mid-cell during cell division. MinE forms a pole-to-pole spatial oscillator with the membrane-bound ATPase MinD, resulting in MinD concentration being the lowest at mid-cell. MinC, the direct inhibitor of the septum initiator protein FtsZ, forms a complex with MinD at the membrane, mirroring its polar gradients. Therefore, MinC-mediated FtsZ inhibition occurs away from mid-cell. Min oscillations are often studied in living cells by time-lapse microscopy using fluorescently labelled Min proteins. Here, we show that, despite permitting oscillations to occur in a range of protein concentrations, the enhanced yellow fluorescent protein (eYFP) C-terminally fused to MinE impairs its function. Combining in vivo, in vitro and in silico approaches, we demonstrate that eYFP compromises the ability of MinE to displace MinC from MinD, to stimulate MinD ATPase activity and to directly bind to the membrane. Moreover, we reveal that MinE-eYFP is prone to aggregation. In silico analyses predict that other fluorescent proteins are also likely to compromise several functionalities of MinE, suggesting that the results presented here are not specific to eYFP.

中文翻译：

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C端eYFP融合会削弱大肠杆菌MinE功能。

大肠杆菌Min系统在细胞分裂过程中在中膜的隔环正确放置方面起着重要作用。MinE与膜结合的ATPase MinD形成一个极对极的空间振荡器，导致MinD浓度在细胞中间最低。隔垫引发剂蛋白FtsZ的直接抑制剂MinC与MinD在膜上形成复合物，反映了其极性梯度。因此，MinC介导的FtsZ抑制发生在中细胞之外。通常使用荧光标记的Min蛋白通过延时显微镜在活细胞中研究Min振荡。在这里，我们表明，尽管允许在一定范围的蛋白质浓度中发生振荡，但与MinE融合的C端增强的黄色荧光蛋白（eYFP）削弱了其功能。结合体内，体外和计算机模拟方法，我们证明eYFP损害了MinE从MinD置换MinC，刺激MinD ATPase活性并直接与膜结合的能力。此外，我们发现MinE-eYFP易于聚集。在计算机分析中预测，其他荧光蛋白也可能损害MinE的几种功能，这表明此处介绍的结果并非特定于eYFP。