Machado Luciana E S F, Castellen Patricia, Blasios Valdir, Ribeiro-Filho Helder V, Bisson-Filho Alexandre W, Benites Pariente Jhonatan S, Nogueira Maria L C, Sforça Mauricio, Honorato Rodrigo V, Lopes-de-Oliveira Paulo S, Salinas Roberto K, Andreu José M, Zeri Ana C, Gueiros-Filho Frederico J
Departamento de Bioquímica, IQ, Universidade de São Paulo, São Paulo, Brazil.
Departamento de Bioquímica, IQ, Universidade de São Paulo, São Paulo, Brazil; Brazilian Biosciences National Laboratory, LNBio, Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, Brazil.
J Biol Chem. 2025 Mar;301(3):108169. doi: 10.1016/j.jbc.2025.108169. Epub 2025 Jan 9.
The Min system is a key spatial regulator of cell division in rod-shaped bacteria and the first FtsZ-negative modulator to be recognized. Nevertheless, despite extensive genetic and in vitro studies, the molecular mechanism used by MinC to inhibit Z-ring formation remains incompletely understood. The crystallization of FtsZ in complex with other negative regulators such as SulA and MciZ has provided important structural information to corroborate in vitro experiments and establish the mechanism of Z-ring antagonism by these modulators. However, MinC and FtsZ have so far eluded co-crystallization, probably because their complex is too unstable to be crystallized. To gain structural insight into the mechanism of action of MinC, we determined the solution structure of the N-terminal domain of Bacillus subtilis MinC, and through NMR titration experiments and mutagenesis identified the binding interfaces involved in the MinC-FtsZ interaction. By using our experimental results as restraints in docking, we also constructed a molecular model for the FtsZ:MinC complex and validated it by molecular dynamics. The model shows that MinC binding overlaps with the FtsZ polymerization interface on the C-terminal globular subdomain of FtsZ and, thus, provides a structural basis for MinC inhibition of FtsZ filament formation. Given that the C-terminal polymerization interface of FtsZ corresponds to the plus end of FtsZ filaments, we propose that capping is the main mechanism employed by MinC to antagonize FtsZ polymerization.
Min系统是杆状细菌细胞分裂的关键空间调节因子，也是首个被识别的FtsZ负调控因子。然而，尽管进行了广泛的遗传学和体外研究，但MinC抑制Z环形成的分子机制仍未完全清楚。FtsZ与其他负调控因子（如SulA和MciZ）形成复合物的晶体结构，为证实体外实验和确定这些调控因子拮抗Z环的机制提供了重要的结构信息。然而，到目前为止，MinC和FtsZ尚未实现共结晶，可能是因为它们的复合物过于不稳定而无法结晶。为了深入了解MinC的作用机制，我们测定了枯草芽孢杆菌MinC N端结构域的溶液结构，并通过核磁共振滴定实验和诱变鉴定了MinC-FtsZ相互作用中涉及的结合界面。通过将实验结果作为对接的限制条件，我们还构建了FtsZ:MinC复合物的分子模型，并通过分子动力学进行了验证。该模型表明，MinC的结合与FtsZ C端球状亚结构域上的FtsZ聚合界面重叠，因此为MinC抑制FtsZ丝状体形成提供了结构基础。鉴于FtsZ的C端聚合界面对应于FtsZ丝状体的正端，我们提出封端是MinC拮抗FtsZ聚合的主要机制。
