title: GTP analogue inhibits polymerization and GTPase activity of the bacterial protein FtsZ without affecting its eukaryotic homologue tubulin.
abstract: The prokaryotic tubulin homologue FtsZ plays a key role in bacterial cell division. Selective inhibitors of the GTP-dependent polymerization of FtsZ are expected to result in a new class of antibacterial agents. One of the challenges is to identify compounds which do not affect the function of tubulin and various other GTPases in eukaryotic cells. We have designed a novel inhibitor of FtsZ polymerization based on the structure of the natural substrate GTP. The inhibitory activity of 8-bromoguanosine 5'-triphosphate (BrGTP) was characterized by a coupled assay, which allows simultaneous detection of the extent of polymerization (via light scattering) and GTPase activity (via release of inorganic phosphate). We found that BrGTP acts as a competitive inhibitor of both FtsZ polymerization and GTPase activity with a Ki for GTPase activity of 31.8 +/- 4.1 microM. The observation that BrGTP seems not to inhibit tubulin assembly suggests a structural difference of the GTP-binding pockets of FtsZ and tubulin.
authors.affiliation: Bioorganic Chemistry, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands.
authors.forename: Tilman
authors.initials: T
authors.lastname: Läppchen
authors.forename: Aloysius F
authors.initials: AF
authors.lastname: Hartog
authors.forename: Victorine A
authors.initials: VA
authors.lastname: Pinas
authors.forename: Gerrit-Jan
authors.initials: GJ
authors.lastname: Koomen
authors.forename: Tanneke
authors.initials: T
authors.lastname: den Blaauwen
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000378:metabolism; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism* / Q000648:ultrastructure; D001667:Binding, Competitive; D002851:Chromatography, High Pressure Liquid; D003598:Cytoskeletal Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism* / Q000648:ultrastructure; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000378:metabolism; D006868:Hydrolysis; D008027:Light; D012542:Scattering, Radiation
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D004791:Enzyme Inhibitors; C071525:FtsZ protein, Bacteria; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases