title: The interactions of cell division protein FtsZ with guanine nucleotides.
abstract: Prokaryotic cell division protein FtsZ, an assembling GTPase, directs the formation of the septosome between daughter cells. FtsZ is an attractive target for the development of new antibiotics. Assembly dynamics of FtsZ is regulated by the binding, hydrolysis, and exchange of GTP. We have determined the energetics of nucleotide binding to model apoFtsZ from Methanococcus jannaschii and studied the kinetics of 2'/3'-O-(N-methylanthraniloyl) (mant)-nucleotide binding and dissociation from FtsZ polymers, employing calorimetric, fluorescence, and stopped-flow methods. FtsZ binds GTP and GDP with K(b) values ranging from 20 to 300 microm(-1) under various conditions. GTP.Mg(2+) and GDP.Mg(2+) bind with slightly reduced affinity. Bound GTP and the coordinated Mg(2+) ion play a minor structural role in FtsZ monomers, but Mg(2+)-assisted GTP hydrolysis triggers polymer disassembly. Mant-GTP binds and dissociates quickly from FtsZ monomers, with approximately 10-fold lower affinity than GTP. Mant-GTP displacement measured by fluorescence anisotropy provides a method to test the binding of any competing molecules to the FtsZ nucleotide site. Mant-GTP is very slowly hydrolyzed and remains exchangeable in FtsZ polymers, but it becomes kinetically stabilized, with a 30-fold slower k(+) and approximately 500-fold slower k(-) than in monomers. The mant-GTP dissociation rate from FtsZ polymers is comparable with the GTP hydrolysis turnover and with the reported subunit turnover in Escherichia coli FtsZ polymers. Although FtsZ polymers can exchange nucleotide, unlike its eukaryotic structural homologue tubulin, GDP dissociation may be slow enough for polymer disassembly to take place first, resulting in FtsZ polymers cycling with GTP hydrolysis similarly to microtubules.
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040, Madrid, Spain. sonia@cib.csic.es
authors.forename: Sonia
authors.initials: S
authors.lastname: Huecas
authors.forename: Claudia
authors.initials: C
authors.lastname: Schaffner-Barbero
authors.forename: Wanius
authors.initials: W
authors.lastname: García
authors.forename: Hugo
authors.initials: H
authors.lastname: Yébenes
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Palacios
authors.forename: José Fernando
authors.initials: JF
authors.lastname: Díaz
authors.forename: Margarita
authors.initials: M
authors.lastname: Menéndez
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Andreu
mesh_terms: D019843:Archaeal Proteins / Q000378:metabolism*; D002152:Calorimetry, Differential Scanning; D002455:Cell Division; D003599:Cytoskeleton / Q000378:metabolism; D006147:Guanine / Q000737:chemistry*; D006153:Guanosine Diphosphate / Q000737:chemistry; D006160:Guanosine Triphosphate / Q000737:chemistry; D006868:Hydrolysis; D007700:Kinetics; D008024:Ligands; D017017:Methanococcus / Q000378:metabolism*; D009711:Nucleotides / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011485:Protein Binding
chemical_list: D019843:Archaeal Proteins; C119586:FtsZ protein, Methanococcus jannaschii; D008024:Ligands; D009711:Nucleotides; D011108:Polymers; D006153:Guanosine Diphosphate; D006147:Guanine; D006160:Guanosine Triphosphate