Trusca D, Scott S, Thompson C, Bramhill D
Department of Enzymology, Merck Research Laboratories, Rahway, New Jersey 07065-0900, USA.
J Bacteriol. 1998 Aug;180(15):3946-53. doi: 10.1128/JB.180.15.3946-3953.1998.
Cell division of Escherichia coli is inhibited when the SulA protein is induced in response to DNA damage as part of the SOS checkpoint control system. The SulA protein interacts with the tubulin-like FtsZ division protein. We investigated the effects of purified SulA upon FtsZ. SulA protein inhibits the polymerization and the GTPase activity of FtsZ, while point mutant SulA proteins show little effect on either of these FtsZ activities. SulA did not inhibit the polymerization of purified FtsZ2 mutant protein, which was originally isolated as insensitive to SulA. These studies define polymerization assays for FtsZ which respond to an authentic cellular regulator. The observations presented here support the notion that polymerization of FtsZ is central to its cellular role and that direct, reversible inhibition of FtsZ polymerization by SulA may account for division inhibition.
作为SOS检查点控制系统的一部分，当响应DNA损伤而诱导SulA蛋白时，大肠杆菌的细胞分裂会受到抑制。SulA蛋白与微管蛋白样FtsZ分裂蛋白相互作用。我们研究了纯化的SulA对FtsZ的影响。SulA蛋白抑制FtsZ的聚合和GTPase活性，而点突变的SulA蛋白对这些FtsZ活性中的任何一种几乎没有影响。SulA不抑制最初分离出的对SulA不敏感的纯化FtsZ2突变蛋白的聚合。这些研究定义了对真实细胞调节剂有反应的FtsZ聚合测定法。此处提出的观察结果支持以下观点：FtsZ的聚合对其细胞作用至关重要，并且SulA对FtsZ聚合的直接、可逆抑制可能是导致分裂抑制的原因。
