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FEBS Lett. 2004 Jul 2;569(1-3):43-8.

Polymerization of nucleotide-free, GDP- and GTP-bound cell division protein FtsZ: GDP makes the difference.

Author information

1
Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain. sonia@cib.csic.es

Abstract

Stable, more than 98% nucleotide-free apo-FtsZ was prepared from purified Methanococcus jannaschhi FtsZ. This facilitates the study of the functional mechanisms of this FtsZ, an assembling GTPase, which shares a common fold with eukaryotic tubulin. Apo-FtsZ underwent cooperative magnesium-induced polymerization with a similar critical concentration and morphology related to that of reconstituted GTP-bound FtsZ, suggesting that the binding of GTP contributes insignificantly to the stability of the FtsZ polymers. On the other hand, reconstituted GDP-FtsZ polymerized with a larger critical concentration than GTP-FtsZ, indicating that GDP binding destabilizes FtsZ polymers. Upon GTP hydrolysis by FtsZ polymers, in the absence of a continued GTP supply and under macromolecular crowding conditions enhancing FtsZ polymerization, the straight GTP polymers disappeared and were replaced by characteristic helically curved GDP-bound polymers. These results suggest that the roles of GTP binding and hydrolysis by this archaeal FtsZ are simply to facilitate disassembly. In a physiological situation in GTP excess, GDP-bound FtsZ subunits could again bind GTP, or trigger disassembly, or be recognized by FtsZ filament depolymerizing proteins, allowing the Z-ring dynamics during prokaryotic cell division.

PMID:
15225606
DOI:
10.1016/j.febslet.2004.05.048
[Indexed for MEDLINE]
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