Peter the Great St.Petersburg Polytechnic University, Polytechnicheskaya 29, Saint-Petersburg, 195251, Russia; Institute of Cytology, Russian Academy of Sciences, Tikhoretsky ave. 4, Saint Petersburg, 194064, Russia.
Peter the Great St.Petersburg Polytechnic University, Polytechnicheskaya 29, Saint-Petersburg, 195251, Russia.
Biochem Biophys Res Commun. 2020 May 14;525(4):948-953. doi: 10.1016/j.bbrc.2020.03.012. Epub 2020 Mar 12.
The SOS response is considered to be an extremely important feature of bacterial cells. It helps them to survive bad times, including helping to develop resistance to antibiotics. The SOS response blocks the cell division. For Escherichia coli it is well known that the SulA protein directly interacts with FtsZ - a key division protein. Now it is believed that fission blocking is based on FtsZ sequestration by the SulA protein, which leads to decrease in effective concentration of FtsZ in the cell below a critical value, which in vitro leads to dismantling of FtsZ polymers. In this work, we demonstrate that in order to block the division of E. coli, it is sufficient to have a relatively small amount of SulA in the cell. Moreover, the analysis of structures formed by FtsZ in E. coli cells under the conditions of SulA protein expression or the SOS response showed that there is no complete disassembly of FtsZ polymers, although Z-rings indeed are not formed. The results of the work indicate that the well-known sequestration mechanism is not comprehensive to explain blocking of the division process by SulA in vivo.
SOS 响应被认为是细菌细胞的一个极其重要的特征。它帮助它们在困难时期生存，包括帮助产生对抗生素的耐药性。SOS 响应阻止细胞分裂。众所周知，对于大肠杆菌来说，SulA 蛋白直接与 FtsZ——一种关键的分裂蛋白相互作用。现在人们相信，分裂阻断是基于 SulA 蛋白对 FtsZ 的隔离，这导致细胞中 FtsZ 的有效浓度降低到临界值以下，在体外导致 FtsZ 聚合物的解体。在这项工作中，我们证明了为了阻止大肠杆菌的分裂，细胞中只需要有相对少量的 SulA 蛋白。此外，在 SulA 蛋白表达或 SOS 响应条件下分析大肠杆菌细胞中形成的 FtsZ 结构表明，虽然 Z 环确实没有形成，但 FtsZ 聚合物并没有完全解体。这项工作的结果表明，众所周知的隔离机制并不全面，无法解释 SulA 在体内阻断分裂过程的机制。
