Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), Grenoble, France.
Univ. Grenoble Alpes, CNRS ERL5261, CEA-IRIG-BCI, INSERM UMR1036, Grenoble, France.
Nat Commun. 2021 May 20;12(1):2987. doi: 10.1038/s41467-021-22957-9.
The elongasome, or Rod system, is a protein complex that controls cell wall formation in rod-shaped bacteria. MreC is a membrane-associated elongasome component that co-localizes with the cytoskeletal element MreB and regulates the activity of cell wall biosynthesis enzymes, in a process that may be dependent on MreC self-association. Here, we use electron cryo-microscopy and X-ray crystallography to determine the structure of a self-associated form of MreC from Pseudomonas aeruginosa in atomic detail. MreC monomers interact in head-to-tail fashion. Longitudinal and lateral interfaces are essential for oligomerization in vitro, and a phylogenetic analysis of proteobacterial MreC sequences indicates the prevalence of the identified interfaces. Our results are consistent with a model where MreC's ability to alternate between self-association and interaction with the cell wall biosynthesis machinery plays a key role in the regulation of elongasome activity.
延长体（Elongasome）或 Rod 系统是一种控制杆状细菌细胞壁形成的蛋白质复合物。MreC 是一种与细胞膜相关的延长体成分，与细胞骨架元件 MreB 共定位，并调节细胞壁生物合成酶的活性，这个过程可能依赖于 MreC 的自我缔合。在这里，我们使用电子晶体显微镜和 X 射线晶体学以原子分辨率确定来自铜绿假单胞菌的自我关联形式的 MreC 结构。MreC 单体以头对头的方式相互作用。纵向和横向界面对于体外寡聚化至关重要，并且对变形菌 MreC 序列的系统发育分析表明存在识别的界面。我们的结果与这样一个模型一致，即 MreC 能够在自我关联和与细胞壁生物合成机制相互作用之间交替，这在调节延长体活性中起着关键作用。
