Jin Jin, Wu Ruijuan, Zhu Jia, Yang Shaoyuan, Lei Zhen, Wang Nan, Singh Vinay K, Zheng Jimin, Jia Zongchao
College of Chemistry, Beijing Normal University, Beijing, China.
Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.
PLoS One. 2015 Feb 6;10(2):e0117823. doi: 10.1371/journal.pone.0117823. eCollection 2015.
YhdE, a Maf-like protein in Escherichia coli, exhibits nucleotide pyrophosphatase (PPase) activity, yet its cellular function remains unknown. Here, we characterized the PPase activity of YhdE on dTTP, UTP and TTP and determined two crystal structures of YhdE, revealing 'closed' and 'open' conformations of an adaptive active site. Our functional studies demonstrated that YhdE retards cell growth by prolonging the lag and log phases, particularly under stress conditions. Morphology studies showed that yhdE-knockout cells transformed the normal rod shape of wild-type cells to a more spherical form, and the cell wall appeared to become more flexible. In contrast, YhdE overexpression resulted in filamentous cells. This study reveals the previously unknown involvement of YhdE in cell growth inhibition under stress conditions, cell-division arrest and cell-shape maintenance, highlighting YhdE's important role in E. coli cell-cycle checkpoints.
YhdE是大肠杆菌中一种类Maf蛋白，具有核苷酸焦磷酸酶（PPase）活性，但其细胞功能仍不清楚。在此，我们表征了YhdE对dTTP、UTP和TTP的PPase活性，并确定了YhdE的两个晶体结构，揭示了适应性活性位点的“闭合”和“开放”构象。我们的功能研究表明，YhdE通过延长延迟期和对数期来延缓细胞生长，特别是在应激条件下。形态学研究表明，敲除yhdE的细胞将野生型细胞的正常杆状形态转变为更球形的形态，并且细胞壁似乎变得更具柔韧性。相反，YhdE的过表达导致细胞呈丝状。这项研究揭示了YhdE以前未知的在应激条件下参与细胞生长抑制、细胞分裂停滞和细胞形态维持的作用，突出了YhdE在大肠杆菌细胞周期检查点中的重要作用。
