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Saini M, Upadhyay N, Dhiman K, Manjhi SK, Kattuparambil AA, Ghoshal A, Arya R, Dey SK, Sharma A, Aduri R, Thelma BK, Ashish F, Kundu S. ARL15, a GTPase implicated in rheumatoid arthritis, potentially repositions its truncated N-terminus as a function of guanine nucleotide binding. Int J Biol Macromol 2024; 254:127898. [PMID: 37939768 DOI: 10.1016/j.ijbiomac.2023.127898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 10/21/2023] [Accepted: 11/03/2023] [Indexed: 11/10/2023]
Abstract
The ADP ribosylation factor like protein 15 (ARL15) gene encodes for an uncharacterized GTPase associated with rheumatoid arthritis (RA) and other metabolic disorders. Investigation of the structural and functional attributes of ARL15 is important to position the protein as a potential drug target. Using spectroscopy, we demonstrated that ARL15 exhibits properties inherent of GTPases. The Km and Vmax of the enzyme were calculated to be 100 μM and 1.47 μmole/min/μL, respectively. The equilibrium dissociation constant (Kd) of GTP binding with ARL15 was estimated to be about eight-fold higher than that of GDP. Small Angle X-ray Scattering (SAXS) data indicated that in solution, the apo state of monomeric ARL15 adopts a shape characterized by a globe of maximum linear dimension (Dmax) of 6.1 nm, and upon binding to GTP or GDP, the vector distribution profile changes to peak-n-tail shoulder with Dmax extended to 7.6 and 7.7 nm, respectively. Structure restoration using a sequence-based template and experimental SAXS data provided the first visual insight revealing that the folded N-terminal in the unbound state of the protein may toggle open upon binding to guanine nucleotides. The conformational dynamics observed in the N-terminal region offer a scope to develop drugs that target this unique GTPase, potentially providing treatments for a range of metabolic disorders.
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Affiliation(s)
- Manisha Saini
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Neelam Upadhyay
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Kanika Dhiman
- CSIR-Institute of Microbial Technology, Chandigarh 160036, India
| | - Satish Kumar Manjhi
- Department of Biological Sciences, Birla Institute of Technology and Science, K K Birla Goa Campus, Goa 403726, India
| | - Aman Achutan Kattuparambil
- Department of Biological Sciences, Birla Institute of Technology and Science, K K Birla Goa Campus, Goa 403726, India
| | - Antara Ghoshal
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Richa Arya
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Sanjay Kumar Dey
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Aditya Sharma
- Department of Genetics, University of Delhi South Campus, New Delhi 110021, India
| | - Raviprasad Aduri
- Department of Biological Sciences, Birla Institute of Technology and Science, K K Birla Goa Campus, Goa 403726, India
| | - B K Thelma
- Department of Genetics, University of Delhi South Campus, New Delhi 110021, India
| | - Fnu Ashish
- CSIR-Institute of Microbial Technology, Chandigarh 160036, India
| | - Suman Kundu
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India; Department of Biological Sciences, Birla Institute of Technology and Science, K K Birla Goa Campus, Goa 403726, India.
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Kumar P, Yadav A, Fishov I, Feingold M. Z-ring Structure and Constriction Dynamics in E. coli. Front Microbiol 2017; 8:1670. [PMID: 28959238 PMCID: PMC5603902 DOI: 10.3389/fmicb.2017.01670] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/17/2017] [Indexed: 12/04/2022] Open
Abstract
The Z-ring plays a central role in bacterial division. It consists of FtsZ filaments, but the way these reorganize in the ring-like structure during septation remains largely unknown. Here, we measure the effective constriction dynamics of the ring. Using an oscillating optical trap, we can switch individual rod-shaped E. coli cells between horizontal and vertical orientations. In the vertical orientation, the fluorescent Z-ring image appears as a symmetric circular structure that renders itself to quantitative analysis. In the horizontal orientation, we use phase-contrast imaging to determine the extent of the cell constriction and obtain the effective time of division. We find evidence that the Z-ring constricts at a faster rate than the cell envelope such that its radial width (inwards from the cytoplasmic membrane) grows during septation. In this respect, our results differ from those recently obtained using photoactivated localization microscopy (PALM) where the radial width of the Z-ring was found to be approximately constant as the ring constricts. A possible reason for the different behavior of the constricting Z-rings could be the significant difference in the corresponding cell growth rates.
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Affiliation(s)
- Pramod Kumar
- Department of Physics, Ben-Gurion University of the NegevBeer Sheva, Israel.,The Ilse Katz Center for Nanotechnology, Ben-Gurion University of the NegevBeer Sheva, Israel
| | - Amarjeet Yadav
- Department of Physics, Ben-Gurion University of the NegevBeer Sheva, Israel.,The Ilse Katz Center for Nanotechnology, Ben-Gurion University of the NegevBeer Sheva, Israel
| | - Itzhak Fishov
- Department of Life Sciences, Ben-Gurion University of the NegevBeer Sheva, Israel
| | - Mario Feingold
- Department of Physics, Ben-Gurion University of the NegevBeer Sheva, Israel.,The Ilse Katz Center for Nanotechnology, Ben-Gurion University of the NegevBeer Sheva, Israel
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3
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Dai L, Huang Y, Chen Y, Long ZE. Cloning and characterization of filamentous temperature-sensitive protein Z from Xanthomonas oryzae pv. Oryzae. SPRINGERPLUS 2016; 5:145. [PMID: 27026842 PMCID: PMC4764595 DOI: 10.1186/s40064-016-1876-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 02/16/2016] [Indexed: 12/03/2022]
Abstract
The ftsZ gene from Xanthomonas oryzae pv. Oryzae was amplified by PCR with the specific primers, and the recombinant plasmid pET-22b-ftsZ was constructed successfully. The FtsZ with a 6× His tag was overexpressed in a soluble form in Escherichia coli BL21 and purified through a Ni-NTA agarose column. The purified recombinant FtsZ showed a single band on SDS-PAGE with an apparent molecular mass of about 44 kDa, and confirmed by western blotting analysis. The optimum temperature for GTPase activity of the recombined FtsZ was 50 °C, and the optimum pH was 7.0. The recombinant FtsZ showed good stability and retained >95 % activity at 50 °C for 240 min. The GTPase activity followed Michaelis–Menten kinetics with the KM of 1.750 mM and the Vmax of 0.155 nmol Pi/min/nmol FtsZ respectively.
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Arjes HA, Lai B, Emelue E, Steinbach A, Levin PA. Mutations in the bacterial cell division protein FtsZ highlight the role of GTP binding and longitudinal subunit interactions in assembly and function. BMC Microbiol 2015; 15:209. [PMID: 26463348 PMCID: PMC4603965 DOI: 10.1186/s12866-015-0544-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/02/2015] [Indexed: 11/28/2022] Open
Abstract
Background Assembly of the tubulin-like GTPase, FtsZ, at the future division site initiates the process of bacterial cytokinesis. The FtsZ ring serves as a platform for assembly of the division machinery and constricts at the leading edge of the invaginating septum during cytokinesis. In vitro, FtsZ assembles in a GTP-dependent manner, forming straight filaments that curve upon GTP hydrolysis. FtsZ binds but cannot hydrolyze GTP as a monomer. Instead, the active site for GTP hydrolysis is formed at the monomer-monomer interface upon dimerization. While the dynamics of GTP hydrolysis and assembly have been extensively studied in vitro, significantly less is known about the role of GTP binding and hydrolysis in vivo. ftsZ84, a GTPase defective allele of Escherichia coli ftsZ, provides a striking example of the disconnect between in vivo and in vitro FtsZ assembly. Results Although ftsZ84 mutants are defective for FtsZ ring formation and division under nonpermissive conditions, they are near wild type for ring formation and division under permissive conditions. In vitro, however, purified FtsZ84 is defective in GTP binding, hydrolysis and assembly under standard reaction conditions. To clarify the nature of the FtsZ84 assembly defect, we isolated and characterized three intragenic suppressors of ftsZ84. All three suppressor mutations increased the apparent affinity of FtsZ84 for GTP, consistent with improved subunit-subunit interactions along the longitudinal interface. Although kinetic analysis indicates that the suppressor mutations increase the affinity of FtsZ84 for GTP, all three exhibit reduced rates of GTP hydrolysis and fail to support assembly in vitro. Conclusion Together, our data suggest that FtsZ, and potentially other enzymes whose assembly is similarly regulated, can compensate for defects in catalysis through increases in substrate binding and subunit-subunit interactions. In addition, these results highlight the dichotomy between commonly used in vitro assembly conditions and FtsZ ring formation in the complex intracellular milieu. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0544-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Heidi A Arjes
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA. .,Present address: Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
| | - Bradley Lai
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | - Ezinwanne Emelue
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | - Adriana Steinbach
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | - Petra Anne Levin
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
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Salvarelli E, Krupka M, Rivas G, Mingorance J, Gómez-Puertas P, Alfonso C, Rico AI. The Cell Division Protein FtsZ from Streptococcus pneumoniae Exhibits a GTPase Activity Delay. J Biol Chem 2015; 290:25081-9. [PMID: 26330552 DOI: 10.1074/jbc.m115.650077] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Indexed: 11/06/2022] Open
Abstract
The cell division protein FtsZ assembles in vitro by a mechanism of cooperative association dependent on GTP, monovalent cations, and Mg(2+). We have analyzed the GTPase activity and assembly dynamics of Streptococcus pneumoniae FtsZ (SpnFtsZ). SpnFtsZ assembled in an apparently cooperative process, with a higher critical concentration than values reported for other FtsZ proteins. It sedimented in the presence of GTP as a high molecular mass polymer with a well defined size and tended to form double-stranded filaments in electron microscope preparations. GTPase activity depended on K(+) and Mg(2+) and was inhibited by Na(+). GTP hydrolysis exhibited a delay that included a lag phase followed by a GTP hydrolysis activation step, until reaction reached the GTPase rate. The lag phase was not found in polymer assembly, suggesting a transition from an initial non-GTP-hydrolyzing polymer that switches to a GTP-hydrolyzing polymer, supporting models that explain FtsZ polymer cooperativity.
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Affiliation(s)
- Estefanía Salvarelli
- From the Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, 28046 Madrid, Spain, Biomol-Informatics S.L., Universidad Autónoma, 28049 Madrid, Spain,
| | | | - Germán Rivas
- the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Jesus Mingorance
- From the Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, 28046 Madrid, Spain
| | - Paulino Gómez-Puertas
- Biomol-Informatics S.L., Universidad Autónoma, 28049 Madrid, Spain, the Molecular Modelling Group, Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain, and
| | - Carlos Alfonso
- the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
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6
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Doxorubicin inhibits E. coli division by interacting at a novel site in FtsZ. Biochem J 2015; 471:335-46. [PMID: 26285656 DOI: 10.1042/bj20150467] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/18/2015] [Indexed: 12/20/2022]
Abstract
The increase in antibiotic resistance has become a major health concern in recent times. It is therefore essential to identify novel antibacterial targets as well as discover and develop new antibacterial agents. FtsZ, a highly conserved bacterial protein, is responsible for the initiation of cell division in bacteria. The functions of FtsZ inside cells are tightly regulated and any perturbation in its functions leads to inhibition of bacterial division. Recent reports indicate that small molecules targeting the functions of FtsZ may be used as leads to develop new antibacterial agents. To identify small molecules targeting FtsZ and inhibiting bacterial division, we screened a U.S. FDA (Food and Drug Administration)-approved drug library of 800 molecules using an independent computational, biochemical and microbial approach. From this screen, we identified doxorubicin, an anthracycline molecule that inhibits Escherichia coli division and forms filamentous cells. A fluorescence-binding assay shows that doxorubicin interacts strongly with FtsZ. A detailed biochemical analysis demonstrated that doxorubicin inhibits FtsZ assembly and its GTPase activity through binding to a site other than the GTP-binding site. Furthermore, using molecular docking, we identified a probable doxorubicin-binding site in FtsZ. A number of single amino acid mutations at the identified binding site in FtsZ resulted in a severalfold decrease in the affinity of FtsZ for doxorubicin, indicating the importance of this site for doxorubicin interaction. The present study suggests the presence of a novel binding site in FtsZ that interacts with the small molecules and can be targeted for the screening and development of new antibacterial agents.
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Duggirala S, Nankar RP, Rajendran S, Doble M. Phytochemicals as Inhibitors of Bacterial Cell Division Protein FtsZ: Coumarins Are Promising Candidates. Appl Biochem Biotechnol 2014; 174:283-96. [DOI: 10.1007/s12010-014-1056-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 07/09/2014] [Indexed: 10/25/2022]
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8
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Ahijado-Guzmán R, Alfonso C, Reija B, Salvarelli E, Mingorance J, Zorrilla S, Monterroso B, Rivas G. Control by potassium of the size distribution of Escherichia coli FtsZ polymers is independent of GTPase activity. J Biol Chem 2013; 288:27358-27365. [PMID: 23940054 DOI: 10.1074/jbc.m113.482943] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The influence of potassium content (at neutral pH and millimolar Mg(2+)) on the size distribution of FtsZ polymers formed in the presence of constantly replenished GTP under steady-state conditions was studied by a combination of biophysical methods. The size of the GTP-FtsZ polymers decreased with lower potassium concentration, in contrast with the increase in the mass of the GDP-FtsZ oligomers, whereas no effect was observed on FtsZ GTPase activity and critical concentration of polymerization. Remarkably, the concerted formation of a narrow size distribution of GTP-FtsZ polymers previously observed at high salt concentration was maintained in all KCl concentrations tested. Polymers induced with guanosine 5'-(α,β-methylene)triphosphate, a slowly hydrolyzable analog of GTP, became larger and polydisperse as the potassium concentration was decreased. Our results suggest that the potassium dependence of the GTP-FtsZ polymer size may be related to changes in the subunit turnover rate that are independent of the GTP hydrolysis rate. The formation of a narrow size distribution of FtsZ polymers under very different solution conditions indicates that it is an inherent feature of FtsZ, not observed in other filament-forming proteins, with potential implications in the structural organization of the functional Z-ring.
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Affiliation(s)
- Rubén Ahijado-Guzmán
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid
| | - Carlos Alfonso
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid
| | - Belén Reija
- Instituto de Química-Física Rocasolano, CSIC, 28006 Madrid
| | - Estefanía Salvarelli
- Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, 28046 Madrid; Biomol Informatics SL, Cantoblanco, 28049 Madrid, Spain
| | - Jesús Mingorance
- Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, 28046 Madrid
| | | | - Begoña Monterroso
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid.
| | - Germán Rivas
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid.
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Rivas G, Alfonso C, Jiménez M, Monterroso B, Zorrilla S. Macromolecular interactions of the bacterial division FtsZ protein: from quantitative biochemistry and crowding to reconstructing minimal divisomes in the test tube. Biophys Rev 2013; 5:63-77. [PMID: 28510160 DOI: 10.1007/s12551-013-0115-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/11/2013] [Indexed: 10/27/2022] Open
Abstract
The division of Escherichia coli is an essential process strictly regulated in time and space. It requires the association of FtsZ with other proteins to assemble a dynamic ring during septation, forming part of the functionally active division machinery, the divisome. FtsZ reversibly interacts with FtsA and ZipA at the cytoplasmic membrane to form a proto-ring, the first molecular assembly of the divisome, which is ultimately joined by the rest of the division-specific proteins. In this review we summarize the quantitative approaches used to study the activity, interactions, and assembly properties of FtsZ under well-defined solution conditions, with the aim of furthering our understanding of how the behavior of FtsZ is controlled by nucleotides and physiological ligands. The modulation of the association and assembly properties of FtsZ by excluded-volume effects, reproducing in part the natural crowded environment in which this protein has evolved to function, will be described. The subsequent studies on the reactivity of FtsZ in membrane-like systems using biochemical, biophysical, and imaging technologies are reported. Finally, we discuss the experimental challenges to be met to achieve construction of the minimum protein set needed to initiate bacterial division, without cells, in a cell-like compartment. This integrated approach, combining quantitative and synthetic strategies, will help to support (or dismiss) conclusions already derived from cellular and molecular analysis and to complete our understanding on how bacterial division works.
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Affiliation(s)
- Germán Rivas
- Centro de Investigaciones Biológicas (CIB), c/Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - Carlos Alfonso
- Centro de Investigaciones Biológicas (CIB), c/Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Mercedes Jiménez
- Centro de Investigaciones Biológicas (CIB), c/Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Begoña Monterroso
- Centro de Investigaciones Biológicas (CIB), c/Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Silvia Zorrilla
- Instituto de Química Física "Rocasolano" (CSIC), c/Serrano 119, 28006, Madrid, Spain
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Martos A, Jiménez M, Rivas G, Schwille P. Towards a bottom-up reconstitution of bacterial cell division. Trends Cell Biol 2012; 22:634-43. [DOI: 10.1016/j.tcb.2012.09.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/05/2012] [Accepted: 09/07/2012] [Indexed: 10/27/2022]
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Monterroso B, Ahijado-Guzmán R, Reija B, Alfonso C, Zorrilla S, Minton AP, Rivas G. Mg(2+)-linked self-assembly of FtsZ in the presence of GTP or a GTP analogue involves the concerted formation of a narrow size distribution of oligomeric species. Biochemistry 2012; 51:4541-50. [PMID: 22568594 PMCID: PMC3448011 DOI: 10.1021/bi300401b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The assembly of the bacterial cell division FtsZ protein in the presence of constantly replenished GTP was studied as a function of Mg(2+) concentration (at neutral pH and 0.5 M potassium) under steady-state conditions by sedimentation velocity, concentration-gradient light scattering, fluorescence correlation spectroscopy, and dynamic light scattering. Sedimentation velocity measurements confirmed previous results indicating cooperative appearance of a narrow size distribution of finite oligomers with increasing protein concentration. The concentration dependence of light scattering and diffusion coefficients independently verified the cooperative appearance of a narrow distribution of high molecular weight oligomers, and in addition provided a measurement of the average size of these species, which corresponds to 100 ± 20 FtsZ protomers at millimolar Mg(2+) concentration. Parallel experiments on solutions containing guanosine-5'-[(α,β)-methyleno]triphosphate, sodium salt (GMPCPP), a slowly hydrolyzable analogue of GTP, in place of GTP, likewise indicated the concerted formation of a narrow size distribution of fibrillar oligomers with a larger average mass (corresponding to 160 ± 20 FtsZ monomers). The closely similar behavior of FtsZ in the presence of both GTP and GMPCPP suggests that the observations reflect equilibrium rather than nonequilibrium steady-state properties of both solutions and exhibit parallel manifestations of a common association scheme.
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Affiliation(s)
- Begoña Monterroso
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Rubén Ahijado-Guzmán
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Belén Reija
- Instituto de Química-Física “Rocasolano”, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carlos Alfonso
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Silvia Zorrilla
- Instituto de Química-Física “Rocasolano”, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Allen P. Minton
- Section on Physical Biochemistry, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Germán Rivas
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Depolymerization dynamics of individual filaments of bacterial cytoskeletal protein FtsZ. Proc Natl Acad Sci U S A 2012; 109:8133-8. [PMID: 22566654 DOI: 10.1073/pnas.1204844109] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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.
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Molecular dynamics simulation of GTPase activity in polymers of the cell division protein FtsZ. FEBS Lett 2012; 586:1236-9. [PMID: 22575662 DOI: 10.1016/j.febslet.2012.03.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 02/01/2012] [Accepted: 03/20/2012] [Indexed: 11/22/2022]
Abstract
FtsZ, the prokaryotic ortholog of tubulin, assembles into polymers in the bacterial division ring. The interfaces between monomers contain a GTP molecule, but the relationship between polymerization and GTPase activity is not unequivocally proven. A set of short FtsZ polymers were modelled and the formation of active GTPase structures was monitored using molecular dynamics. Only the interfaces nearest the polymer ends exhibited an adequate geometry for GTP hydrolysis. Simulated conversion of interfaces from close-to-end to internal position and vice versa resulted in their spontaneous rearrangement between active and inactive conformations. This predicted behavior of FtsZ polymer ends was supported by in vitro experiments.
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