title: Tetramerization of ZapA is required for FtsZ bundling.
abstract: Prokaryotic cell division is a highly orchestrated process requiring the formation of a wide range of biomolecular complexes, perhaps the most important of these involving the prokaryotic tubulin homologue FtsZ, a fibre-forming GTPase. FtsZ assembles into a ring (the Z-ring) on the inner surface of the inner membrane at the site of cell division. The Z-ring then acts as a recruitment site for at least ten other proteins which form the division apparatus. One of these proteins, ZapA, acts to enhance lateral associations between FtsZ fibres to form bundles. Previously we have expressed, purified and crystallized ZapA and demonstrated that it exists as a tetramer. We also showed that ZapA binds to FtsZ polymers, strongly promoting their bundling, while inhibiting FtsZ GTPase activity by inducing conformational changes in the bound nucleotide. In the present study we investigate the importance of the tetramerization of ZapA on its function. We generated a number of mutant forms of ZapA with the aim of disrupting the dimer-dimer interface. We show that one of these mutants, I83E, is fully folded and binds to FtsZ, but is a constitutive dimer. Using this mutant we show that tetramerization is a requirement for both FtsZ bundling and GTPase modulation activities.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT, UK.
authors.forename: Raúl
authors.initials: R
authors.lastname: Pacheco-Gómez
authors.forename: Xi
authors.initials: X
authors.lastname: Cheng
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hicks
authors.forename: Corinne J I
authors.initials: CJ
authors.lastname: Smith
authors.forename: David I
authors.initials: DI
authors.lastname: Roper
authors.forename: Stephen
authors.initials: S
authors.lastname: Addinall
authors.forename: Alison
authors.initials: A
authors.lastname: Rodger
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Dafforn
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D048749:Cytokinesis / Q000235:genetics / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; D050505:Mutant Proteins; D011994:Recombinant Proteins; C520744:ZapA protein, E coli; D006160:Guanosine Triphosphate