MinD and role of the deviant Walker A motif, dimerization and membrane binding in oscillation

Authors

  • Joe Lutkenhaus,

    Corresponding author
    1. Department of Microbiology, Molecular Genetics and Immunology, and
    • For correspondence. E-mail jlutkenh@kumc.edu ; Tel. (+1) 913 588 7054; Fax (+1) 913 588 7295.

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  • M. Sundaramoorthy

    1. Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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    • Present address: Departments of Medicine and Biochemistry, Vanderbilt University Medical Center, 1161 Twenty-first Avenue South, Nashville, TN 37232–2372, USA.


Summary

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.

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