Zhou Huaijin, Schulze Ryan, Cox Sandra, Saez Cristian, Hu Zonglin, Lutkenhaus Joe
Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
J Bacteriol. 2005 Jan;187(2):629-38. doi: 10.1128/JB.187.2.629-638.2005.
The MinD ATPase is critical to the oscillation of the Min proteins, which limits formation of the Z ring to midcell. In the presence of ATP, MinD binds to the membrane and recruits MinC, forming a complex that can destabilize the cytokinetic Z ring. MinE, which is also recruited to the membrane by MinD, displaces MinC and stimulates the MinD ATPase, resulting in the oscillation of the Min proteins. In this study we have investigated the role of lysine 11, present in the deviant Walker A motif of MinD, and the three residues in helix 7 (E146, S148, and D152) that interact electrostatically with lysine 11. Lysine 11 is required for interaction of MinD with the membrane, MinC, MinE, and itself. In contrast, the three residues in helix 7 that interact with lysine 11 are not required for binding to the membrane or activation of MinC. They are also not required for MinE binding; however, they are required for MinE to stimulate the MinD ATPase. Interestingly, the D152A mutant self-interacts, binds to the membrane, and recruits MinC and MinE in the presence of ADP as well as ATP. This mutant provides evidence that dimerization of MinD is sufficient for MinD to bind the membrane and recruit its partners.
MinD ATP酶对于Min蛋白的振荡至关重要，Min蛋白的振荡将Z环的形成限制在细胞中部。在ATP存在的情况下，MinD与细胞膜结合并招募MinC，形成一种能使细胞分裂Z环不稳定的复合物。同样由MinD招募至细胞膜的MinE，取代MinC并刺激MinD ATP酶，从而导致Min蛋白的振荡。在本研究中，我们研究了MinD异常的沃克A基序中赖氨酸11的作用，以及螺旋7中的三个残基（E146、S148和D152），它们与赖氨酸11发生静电相互作用。赖氨酸11是MinD与细胞膜、MinC、MinE及其自身相互作用所必需的。相比之下，螺旋7中与赖氨酸11相互作用的三个残基对于与细胞膜结合或激活MinC并非必需。它们对于MinE结合也不是必需的；然而，它们是MinE刺激MinD ATP酶所必需的。有趣的是，D152A突变体在ADP以及ATP存在的情况下会发生自我相互作用、与细胞膜结合并招募MinC和MinE。该突变体提供了证据，表明MinD的二聚化足以使MinD结合细胞膜并招募其伙伴。
