Lutkenhaus Joe, Sundaramoorthy M
Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
Mol Microbiol. 2003 Apr;48(2):295-303. doi: 10.1046/j.1365-2958.2003.03427.x.
The ATPase activity of MinD is required for it to oscillate between the ends of the cell and spatially regulate cell division in Escherichia coli. It is a member of a functionally diverse subgroup of ATPases which are involved in activities ranging from nitrogen fixation (NifH) to plasmid segregation (ParA). All members of the subgroup have a deviant Walker A motif which contains a conserved 'signature' lysine that characterizes this subgroup. In the NifH homodimer the signature lysines make intermonomer contact with the bound nucleotides indicating a role in ATP hydrolysis. ATP binding to NifH leads to formation of an active dimer that associates with a partner that is also a dimer. Because ATP hydrolysis is coupled to formation of the complex, the complex is only transient. In the presence of ATP MinD binds MinC and goes to the membrane, however, the ATPase is not stimulated and the complex is stable. Subsequent interaction of this complex with MinE, however, leads to ATPase stimulation and release of the Min proteins from the membrane. The sequential interaction of MinD with these two proteins, which is dictated by the membrane, is critical to the oscillatory mechanism involved in spatial regulation of division.
MinD的ATP酶活性是其在大肠杆菌细胞两端之间振荡并在空间上调节细胞分裂所必需的。它是ATP酶功能多样的亚组的成员，这些ATP酶参与从固氮（NifH）到质粒分离（ParA）等各种活动。该亚组的所有成员都有一个异常的沃克A基序，其中包含一个保守的“特征”赖氨酸，它是该亚组的特征。在NifH同型二聚体中，特征赖氨酸与结合的核苷酸形成单体间接触，表明其在ATP水解中起作用。ATP与NifH结合导致形成一个活性二聚体，该二聚体与同样是二聚体的伙伴结合。由于ATP水解与复合物的形成偶联，所以该复合物只是短暂存在。在ATP存在的情况下，MinD与MinC结合并前往细胞膜，然而，ATP酶未被激活，复合物是稳定的。然而，该复合物随后与MinE相互作用，导致ATP酶被激活，Min蛋白从细胞膜上释放。MinD与这两种蛋白质的顺序相互作用由细胞膜决定，这对于参与分裂空间调节的振荡机制至关重要。
