Control by potassium of the size distribution of Escherichia coli FtsZ polymers is independent of GTPase activity.
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.
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid.
Rubén
R
Ahijado-Guzmán
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid.
Carlos
C
Alfonso
Instituto de Química-Física Rocasolano, CSIC, 28006 Madrid.
Belén
B
Reija
Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, 28046 Madrid; Biomol Informatics SL, Cantoblanco, 28049 Madrid, Spain.
Estefanía
E
Salvarelli
Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, 28046 Madrid.
Jesús
J
Mingorance
Instituto de Química-Física Rocasolano, CSIC, 28006 Madrid.
Silvia
S
Zorrilla
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid. Electronic address: monterroso@cib.csic.es.
Begoña
B
Monterroso
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid. Electronic address: grivas@cib.csic.es.
Germán
G
Rivas
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011188:Potassium / Q000737:chemistry* / Q000378:metabolism; D055503:Protein Multimerization / Q000502:physiology*; D020836:Protein Structure, Quaternary
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D011188:Potassium
Biophysics; Cell Division; GTPase; Protein Assembly; Protein-Protein Interactions