title: Depolymerization dynamics of individual filaments of bacterial cytoskeletal protein FtsZ.
abstract: We report observation and analysis of the depolymerization filaments of the bacterial cytoskeletal protein FtsZ (filament temperature-sensitive Z) formed on a mica surface. At low concentration, proteins adsorbed on the surface polymerize forming curved filaments that close into rings that remain stable for some time before opening irreversibly and fully depolymerizing. The distribution of ring lifetimes (T) as a function of length (N), shows that the rate of ring aperture correlates with filament length. If this ring lifetime is expressed as a bond survival time, (T(b) ≡ NT), this correlation is abolished, indicating that these rupture events occur randomly and independently at each monomer interface. After rings open irreversibly, depolymerization of the remaining filaments is fast, but can be slowed down and followed using a nonhydrolyzing GTP analogue. The histogram of depolymerization velocities of individual filaments has an asymmetric distribution that can be fit with a computer model that assumes two rupture rates, a slow one similar to the one observed for ring aperture, affecting monomers in the central part of the filaments, and a faster one affecting monomers closer to the open ends. From the quantitative analysis, we conclude that the depolymerization rate is affected both by nucleotide hydrolysis rate and by its exchange along the filament, that all monomer interfaces are equally competent for hydrolysis, although depolymerization is faster at the open ends than in central filament regions, and that all monomer-monomer interactions, regardless of the nucleotide present, can adopt a curved configuration.
authors.affiliation: Instituto de Ciencia de Materiales Nicolás Cabrera, C-8, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Mateos-Gil
authors.forename: Alfonso
authors.initials: A
authors.lastname: Paez
authors.forename: Ines
authors.initials: I
authors.lastname: Hörger
authors.forename: Germán
authors.initials: G
authors.lastname: Rivas
authors.forename: Miguel
authors.initials: M
authors.lastname: Vicente
authors.forename: Pedro
authors.initials: P
authors.lastname: Tarazona
authors.forename: Marisela
authors.initials: M
authors.lastname: Vélez
mesh_terms: D000538:Aluminum Silicates; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D003198:Computer Simulation; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000378:metabolism; D003599:Cytoskeleton / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D058105:Polymerization; D054730:Protein Interaction Domains and Motifs / Q000502:physiology
chemical_list: D000538:Aluminum Silicates; D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; D006160:Guanosine Triphosphate; C011934:mica