title: Structural insights into FtsZ protofilament formation.
abstract: The prokaryotic tubulin homolog FtsZ polymerizes into a ring structure essential for bacterial cell division. We have used refolded FtsZ to crystallize a tubulin-like protofilament. The N- and C-terminal domains of two consecutive subunits in the filament assemble to form the GTPase site, with the C-terminal domain providing water-polarizing residues. A domain-swapped structure of FtsZ and biochemical data on purified N- and C-terminal domains show that they are independent. This leads to a model of how FtsZ and tubulin polymerization evolved by fusing two domains. In polymerized tubulin, the nucleotide-binding pocket is occluded, which leads to nucleotide exchange being the rate-limiting step and to dynamic instability. In our FtsZ filament structure the nucleotide is exchangeable, explaining why, in this filament, nucleotide hydrolysis is the rate-limiting step during FtsZ polymerization. Furthermore, crystal structures of FtsZ in different nucleotide states reveal notably few differences.
authors.affiliation: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Oliva
authors.forename: Suzanne C
authors.initials: SC
authors.lastname: Cordell
authors.forename: Jan
authors.initials: J
authors.lastname: Löwe
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D001665:Binding Sites; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D019281:Dimerization; D020558:GTP Phosphohydrolases / Q000378:metabolism; D017017:Methanococcus / Q000737:chemistry / Q000378:metabolism; D008854:Microscopy, Electron; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary; D020124:Thermotoga maritima / Q000737:chemistry* / Q000235:genetics; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism; D014867:Water / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; D014404:Tubulin; D014867:Water; D020558:GTP Phosphohydrolases