Abstract
The stability, refolding, and assembly properties of FtsZ cell division proteins from Methanococcus jannaschii and Escherichia coli have been investigated. Their guanidinium chloride unfolding has been studied by circular dichroism spectroscopy. FtsZ from E. coli and tubulin released the bound guanine nucleotide, coinciding with an initial unfolding stage at low denaturant concentrations, followed by unfolding of the apoprotein. FtsZ from M. jannaschii released its nucleotide without any detectable secondary structural change. It unfolded in an apparently two-state transition at larger denaturant concentrations. Isolated FtsZ polypeptide chains were capable of spontaneous refolding and GTP-dependent assembly. The homologous eukaryotic tubulin monomers misfold in solution, but fold within the cytosolic chaperonin CCT. Analysis of the extensive tubulin loop insertions in the FtsZ/tubulin common core and of the intermolecular contacts in model microtubules and tubulin-CCT complexes shows a loop insertion present at every element of lateral protofilament contact and at every contact of tubulin with CCT (except at loop T7). The polymers formed by purified FtsZ have a distinct limited protofilament association in comparison with microtubules. We propose that the loop insertions of tubulin and its CCT-assisted folding coevolved with the lateral association interfaces responsible for extended two-dimensional polymerization into microtubule polymers.
Highlights
The stability, refolding, and assembly properties of FtsZ cell division proteins from Methanococcus jannaschii and Escherichia coli have been investigated
We propose that the loop insertions of tubulin and its CCT-assisted folding coevolved with the lateral association interfaces responsible for extended two-dimensional polymerization into microtubule polymers
M. jannaschii FtsZ unfolded in a single stage at higher guanidinium chloride (GdmCl) concentrations at 25 °C; it released its nucleotide at lower denaturant concentrations
Summary
The stability, refolding, and assembly properties of FtsZ cell division proteins from Methanococcus jannaschii and Escherichia coli have been investigated. Their guanidinium chloride unfolding has been studied by circular dichroism spectroscopy. Archaeal FtsZ from Methanococcus jannaschii [2] and eukaryotic tubulin [5] share a common core of folded N-terminal nucleotide-binding and middle structural domains. We further analyzed the structures and assemblies of FtsZ and tubulin, which suggest that the loop insertions of tubulin and its CCT-assisted folding coevolved with the lateral association interfaces responsible for two-dimensional polymerization into microtubules
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
