title: Essential cell division protein FtsZ assembles into one monomer-thick ribbons under conditions resembling the crowded intracellular environment.
abstract: Experimental conditions that simulate the crowded bacterial cytoplasmic environment have been used to study the assembly of the essential cell division protein FtsZ from Escherichia coli. In solutions containing a suitable concentration of physiological osmolytes, macromolecular crowding promotes the GTP-dependent assembly of FtsZ into dynamic two-dimensional polymers that disassemble upon GTP depletion. Atomic force microscopy reveals that these FtsZ polymers adopt the shape of ribbons that are one subunit thick. When compared with the FtsZ filaments observed in vitro in the absence of crowding, the ribbons show a lag in the GTPase activity and a decrease in the GTPase rate and in the rate of GTP exchange within the polymer. We propose that, in the crowded bacterial cytoplasm under assembly-promoting conditions, the FtsZ filaments tend to align forming dynamic ribbon polymers. In vivo these ribbons would fit into the Z-ring even in the absence of other interactions. Therefore, the presence of mechanisms to prevent the spontaneous assembly of the Z-ring in non-dividing cells must be invoked.
authors.affiliation: Centro de Investigaciones Biológicas, Universidad Autónoma, Madrid, Spain.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: González
authors.forename: Mercedes
authors.initials: M
authors.lastname: Jiménez
authors.forename: Marisela
authors.initials: M
authors.lastname: Vélez
authors.forename: Jesús
authors.initials: J
authors.lastname: Mingorance
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Andreu
authors.forename: Miguel
authors.initials: M
authors.lastname: Vicente
authors.forename: Germán
authors.initials: G
authors.lastname: Rivas
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins / Q000737:chemistry*; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D008958:Models, Molecular
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate