An equilibrium model for the Mg(2+)-linked self-assembly of FtsZ in the presence of GTP or a GTP analogue.
The concerted formation of a narrow distribution of oligomeric FtsZ species in the presence of GTP or a GTP analogue under close to physiological conditions (neutral pH and 0.5 M K(+)) has been characterized recently by various biophysical methods [Monterroso, B., et al. (2012) Biochemistry 51, 4541-4550]. An equilibrium model may semiquantitatively account for the results of this study; in the model, FtsZ self-associates in a noncooperative fashion to form linear fibrils, that upon increasing to a certain size exhibit an increasing tendency to form closed cyclic fibrils, as previously suggested [González, J. M., et al. (2005) Proc. Natl. Acad. Sci. U.S.A. 102, 1895-1900]. The closed cyclic fibrils are formed when the natural curvature and flexibility of a linear oligomer bring the ends of a linear fiber sufficiently close to overcome the entropic barrier to loop closure. The size distribution of cyclic oligomers is thus a reflection of the tendency toward curvature of linear fibrils of FtsZ under the conditions used in these experiments.
Chemical and Physical Biology Program, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Begoña
B
Monterroso
Germán
G
Rivas
Allen P
AP
Minton
D003598:Cytoskeletal Proteins / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D008027:Light; D008274:Magnesium / Q000378:metabolism* / Q000494:pharmacology; D008954:Models, Biological; D055503:Protein Multimerization / Q000187:drug effects*; D017433:Protein Structure, Secondary; D012399:Rotation; D012542:Scattering, Radiation
D003598:Cytoskeletal Proteins; C004805:5'-guanylylmethylenebisphosphonate; D006160:Guanosine Triphosphate; D008274:Magnesium