Cleverley Robert M, Barrett Jeffrey R, Baslé Arnaud, Bui Nhat Khai, Hewitt Lorraine, Solovyova Alexandra, Xu Zhi-Qiang, Daniel Richard A, Dixon Nicholas E, Harry Elizabeth J, Oakley Aaron J, Vollmer Waldemar, Lewis Richard J
Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia.
Nat Commun. 2014 Nov 18;5:5421. doi: 10.1038/ncomms6421.
Bacterial cell division is facilitated by a molecular machine--the divisome--that assembles at mid-cell in dividing cells. The formation of the cytokinetic Z-ring by the tubulin homologue FtsZ is regulated by several factors, including the divisome component EzrA. Here we describe the structure of the 60-kDa cytoplasmic domain of EzrA, which comprises five linear repeats of an unusual triple helical bundle. The EzrA structure is bent into a semicircle, providing the protein with the potential to interact at both N- and C-termini with adjacent membrane-bound divisome components. We also identify at least two binding sites for FtsZ on EzrA and map regions of EzrA that are responsible for regulating FtsZ assembly. The individual repeats, and their linear organization, are homologous to the spectrin proteins that connect actin filaments to the membrane in eukaryotes, and we thus propose that EzrA is the founding member of the bacterial spectrin family.
细菌细胞分裂由一种分子机器——分裂体促进，分裂体在正在分裂的细胞的细胞中部组装。微管蛋白同源物FtsZ形成细胞分裂的Z环受多种因素调控，包括分裂体组分EzrA。本文我们描述了EzrA 60 kDa细胞质结构域的结构，它由一个不寻常的三螺旋束的五个线性重复序列组成。EzrA结构弯曲成一个半圆，使该蛋白有可能在N端和C端与相邻的膜结合分裂体组分相互作用。我们还确定了EzrA上FtsZ的至少两个结合位点，并绘制了EzrA中负责调节FtsZ组装的区域。这些单个的重复序列及其线性排列与真核生物中连接肌动蛋白丝与膜的血影蛋白家族同源，因此我们提出EzrA是细菌血影蛋白家族的创始成员。
