The polymerization mechanism of the bacterial cell division protein FtsZ

Scheffers, Dirk‐Jan; Driessen, Arnold J. M.

doi:10.1016/s0014-5793(01)02855-1

Cited by 60 publications

(33 citation statements)

References 56 publications

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“…2B). Because buried SASA provides a qualitative estimate for the strength of monomer-monomer association, the consistently lower SASA values observed for the GDP-FtsZ dimer are in accordance with prior results showing that assembly of GDP-FtsZ is weaker than GTP-FtsZ, and that hydrolysis destabilizes FtsZ filaments (15,(26)(27)(28). It is likely that hydrolysis of GTP transitions a relatively straight GTP-FtsZ filament to one that can take on a highly curved conformation while decreasing the association strength between monomers, leading to a filament more prone to depolymerization.…”

supporting

confidence: 90%

Nucleotide-dependent conformations of FtsZ dimers and force generation observed through molecular dynamics simulations

Hsin

Gopinathan

Huang

2012

Proc. Natl. Acad. Sci. U.S.A.

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The bacterial cytoskeletal protein FtsZ is a GTPase that is thought to provide mechanical constriction force via an unidentified mechanism. Purified FtsZ polymerizes into filaments with varying structures in vitro: while GTP-bound FtsZ assembles into straight or gently curved filaments, GDP-bound FtsZ forms highly curved filaments, prompting the hypothesis that a difference in the inherent curvature of FtsZ filaments provides mechanical force. However, no nucleotide-dependent structural transition of FtsZ monomers has been observed to support this force generation model. Here, we present a series of all-atom molecular dynamics simulations probing the effects of nucleotide binding on the structure of an FtsZ dimer. We found that the FtsZ-dimer structure is dependent on nucleotidebinding state. While a GTP-bound FtsZ dimer retained a firm monomer-monomer contact, a GDP-bound FtsZ dimer lost some of the monomer-monomer association, leading to a "hinge-opening" event that resulted in a more bent dimer, while leaving each monomer structure largely unaffected. We constructed models of FtsZ filaments and found that a GDP-FtsZ filament is much more curved than a GTP-FtsZ filament, with the degree of curvature matching prior experimental data. FtsZ dynamics were used to estimate the amount of force an FtsZ filament could exert when hydrolysis occurs (20-30 pN per monomer). This magnitude of force is sufficient to direct inward cell-wall growth during division, and to produce the observed degree of membrane pinching in liposomes. Taken together, our data provide molecular-scale insight on the origin of FtsZ-based constriction force, and the mechanism underlying prokaryotic cell division.bacterial cell division | bacterial cytoskeleton | GTP hydrolysis T he bacterial cell-division protein FtsZ, a tubulin homolog and a GTPase, polymerizes into filaments situated underneath the cytoplasmic membrane at the division site (1-3). The ftsz gene is essential and depletion of FtsZ protein leads to cells unable to divide that instead take on a filamentous morphology (4). During division, rod-shaped bacteria such as Escherichia coli synthesize new hemispherical membrane and cell wall, requiring inward forces. While an array of proteins are needed for division to occur (5, 6), FtsZ alone has been demonstrated to be sufficient for generating inward pinching forces on liposomes in vitro (7-10), and is thought to be the source of the constriction force needed for division.How FtsZ generates mechanical force is still unclear, but several models have been proposed (11), one of which is based on the intrinsic nucleotide-dependent bending of FtsZ filaments (12, 13). In the presence of GTP, purified FtsZ assembles into either straight or gently curved filaments with a radius of curvature of approximately 100 nm, while in the presence of GDP, highly curved filaments form with a radius of curvature of approximately 10 nm (12,14,15). Subsequent theoretical modeling demonstrated that the rapid transition between straight and curved FtsZ filaments...

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supporting

confidence: 90%

Nucleotide-dependent conformations of FtsZ dimers and force generation observed through molecular dynamics simulations

Hsin

Gopinathan

Huang

2012

Proc. Natl. Acad. Sci. U.S.A.

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“…FtsZ subunits within polymers have GDP plus phosphate at their active site and therefore are effectively in their GTP-bound configuration . Scheffers & Driessen (2001 have therefore invoked a GTP-cap model for FtsZ polymerization, similar to that for tubulin. In this model, exchange of guanine nucleotide phosphates takes place at the ends of polymers rather than by diffusion from within polymers.…”

Section: Discussionmentioning

confidence: 99%

Dynamic FtsZ polymerization is sensitive to the GTP to GDP ratio and can be maintained at steady state using a GTP-regeneration system

Small

Addinall

2003

Microbiology

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In vitro polymerization of the essential bacterial cell division protein FtsZ, in the presence of GTP, is rapid and transient due to its efficient binding and hydrolysis of GTP. In contrast, the in vivo polymeric FtsZ structure which drives cell division -the Z-ring -is present in cells for extended periods of time whilst undergoing constant turnover of FtsZ. It is demonstrated that dynamic polymerization of Escherichia coli FtsZ in vitro is sensitive to the ratio of GTP to GDP concentration. Increase of GDP concentration in the presence of a constant GTP concentration reduces both the duration of FtsZ polymerization and the initial light-scattering maximum which occurs upon addition of GTP. It is also demonstrated that by use of a GTP-regeneration system, polymers of FtsZ can be maintained in a steady state for up to 85 min, while preserving their dynamic properties. The authors therefore present the use of a GTP-regeneration system for FtsZ polymerization as an assay more representative of the in vivo situation, where FtsZ polymers are subject to a constant, relatively high GTP to GDP ratio. INTRODUCTIONThe FtsZ protein has a fundamental role in bacterial cell division , is highly conserved throughout the eubacteria and appears to be required for division of chloroplasts, some archaea and some mitochondria (Beech et al., 2000;Vitha et al., 2001;Wang & Lutkenhaus, 1996). FtsZ is a cytoplasmic protein which, at a particular stage in the Escherichia coli cell cycle, locates to the cell centre, forming a polymeric ring (the Z-ring) around the inner circumference of the cytoplasmic membrane Bi & Lutkenhaus, 1991;Dai & Lutkenhaus, 1991; Den Blaauwen et al., 1999;Pla et al., 1991). Invagination of the division septum then follows the shape of the Z-ring as it reduces in diameter until septation is complete Bi & Lutkenhaus, 1991. FtsZ is strongly related to a/b-tubulin in terms of threedimensional structure (Lowe & Amos, 1998), the possession of GTPase activity (de Boer et al., 1992;Mukherjee et al., 1993;RayChaudhuri & Park, 1992) and the ability to polymerize in a nucleotide-dependent manner in vitro (Erickson et al., 1996;. Indeed, FtsZ forms a variety of polymeric structures in vitro depending on experimental conditions (Erickson et al., 1996;Lowe & Amos, 1999, 2000Yu & Margolin, 1997); however, all of these represent different arrangements of linear protofilaments.There have been multiple studies of the dynamics of FtsZ polymerization in vitro. In the presence of GDP (Rivas et al., 2000(Rivas et al., , 2001 Sossong et al., 1999) or in the presence of GTP under particular conditions where only single protofilaments are formed (Romberg et al., 2001), polymerization is proposed to be isodesmic. Under conditions where FtsZ forms more complex polymers, polymerization and the GTPase activity are co-operative (Caplan & Erickson, 2003;Mukherjee & Lutkenhaus, 1999;White et al., 2000).The technique of right-angled light-scattering has proved useful for real-time monitoring of FtsZ polymerization (Mingorance et al., 2001;...

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“…This buffer with a high potassium content, which increases the intrinsic GTPase activity of E. coli FtsZ and therefore the rate of disassembly of FtsZ filaments (for a recent review see Ref. 28), makes it difficult to get stable FtsZ polymers during the time-scale (Ͼ10 min) of most of the experiments performed in this work (mainly those done in the absence of crowding agents, see below). In these experiments the GTP was regenerated by adding to the solution an enzymatic regeneration system (1 unit/ml acetate kinase plus 15 mM acetyl phosphate, both from Sigma), as adapted from tubulin/microtubules studies (30).…”

Section: Methodsmentioning

confidence: 99%

Essential Cell Division Protein FtsZ Assembles into One Monomer-thick Ribbons under Conditions Resembling the Crowded Intracellular Environment

González

Jiménez

Vélez

et al. 2003

Journal of Biological Chemistry

173

227

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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.

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The polymerization mechanism of the bacterial cell division protein FtsZ

Cited by 60 publications

References 56 publications

Nucleotide-dependent conformations of FtsZ dimers and force generation observed through molecular dynamics simulations

Nucleotide-dependent conformations of FtsZ dimers and force generation observed through molecular dynamics simulations

Dynamic FtsZ polymerization is sensitive to the GTP to GDP ratio and can be maintained at steady state using a GTP-regeneration system

Essential Cell Division Protein FtsZ Assembles into One Monomer-thick Ribbons under Conditions Resembling the Crowded Intracellular Environment

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