title: FtsZ polymer-bundling by the Escherichia coli ZapA orthologue, YgfE, involves a conformational change in bound GTP.
abstract: Cell division is a fundamental process for both eukaryotic and prokaryotic cells. In bacteria, cell division is driven by a dynamic, ring-shaped, cytoskeletal element (the Z-ring) made up of polymers of the tubulin-like protein FtsZ. It is thought that lateral associations between FtsZ polymers are important for function of the Z-ring in vivo, and that these interactions are regulated by accessory cell division proteins such as ZipA, EzrA and ZapA. We demonstrate that the putative Escherichia coli ZapA orthologue, YgfE, exists in a dimer/tetramer equilibrium in solution, binds to FtsZ polymers, strongly promotes FtsZ polymer bundling and is a potent inhibitor of the FtsZ GTPase activity. We use linear dichroism, a technique that allows structure analysis of molecules within linear polymers, to reveal a specific conformational change in GTP bound to FtsZ polymers, upon bundling by YgfE. We show that the consequences of FtsZ polymer bundling by YgfE and divalent cations are very similar in terms of GTPase activity, bundle morphology and GTP orientation and therefore propose that this conformational change in bound GTP reveals a general mechanism of FtsZ bundling.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.
authors.forename: Elaine
authors.initials: E
authors.lastname: Small
authors.forename: Rachel
authors.initials: R
authors.lastname: Marrington
authors.forename: Alison
authors.initials: A
authors.lastname: Rodger
authors.forename: David J
authors.initials: DJ
authors.lastname: Scott
authors.forename: Katherine
authors.initials: K
authors.lastname: Sloan
authors.forename: David
authors.initials: D
authors.lastname: Roper
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Dafforn
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Addinall
mesh_terms: D001704:Biopolymers / Q000378:metabolism*; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000737:chemistry*; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017386:Sequence Homology, Amino Acid; D017186:Titrimetry
chemical_list: D001704:Biopolymers; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C076835:FtsZ84 protein, E coli; C520744:ZapA protein, E coli; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases