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Polymerization of nucleotide‐free, GDP‐ and GTP‐bound cell division protein FtsZ: GDP makes the difference
Author(s) -
Huecas Sonia,
Andreu José Manuel
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.05.048
Subject(s) - ftsz , gtp' , gtpase , guanosine diphosphate , cell division , cytoskeleton , tubulin , biophysics , guanosine triphosphate , biology , biochemistry , microbiology and biotechnology , chemistry , cell , enzyme , microtubule
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.