Escherichia coli cell-division gene ftsZ encodes a novel GTP-binding protein.
Escherichia coli divides by forming a septum across the middle of the cell. The biochemical mechanism underlying this process is unknown. Genetic evidence suggests that of all the fts (filamentation temperature sensitive) genes involved in E. coli cell division, ftsZ plays a central role at the earliest known step of septation. Here we show that FtsZ protein binds GTP in vitro using unusual sequence elements. In contrast, such binding to the product of the conditional-lethal ftsZ84 allele is impaired. Purified FtsZ displays a Mg(2+)-dependent GTPase activity which is markedly reduced in the FtsZ84 protein. FtsZ copurifies with near stoichiometric amounts of noncovalently-bound GDP, implying the presence of a GTPase cycle in vivo, similar to that known for signal-transducing GTP-binding proteins. We also show that a small fraction of FtsZ exists as a distinct membrane-associated species that binds GTP. The membrane association of FtsZ and the known ability of GTPases to act as molecular switches implicate FtsZ in a GTP-activated signal transduction pathway that may regulate the start of septation in E. coli.
RayChaudhuri
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Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111.
Park
J T
JT
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D002455:Cell Division / Q000235:genetics; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D015342:DNA Probes; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins; D019204:GTP-Binding Proteins / Q000502:physiology*; D005798:Genes, Bacterial / Q000502:physiology*; D006160:Guanosine Triphosphate / Q000378:metabolism; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D013997:Time Factors
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D015342:DNA Probes; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; C076835:FtsZ84 protein, E coli; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins