We have studied the assembly and GTPase of purified FtsZ from the hyperthermophilic archaeon Meth... more We have studied the assembly and GTPase of purified FtsZ from the hyperthermophilic archaeon Methanococcus jannaschii, a structural homolog of eukaryotic tubulin, employing wild-type FtsZ, FtsZ-His 6 (histidinetagged FtsZ), and the new mutants FtsZ-W319Y and FtsZ-W319Y-His 6 , with light scattering, nucleotide analyses, electron microscopy, and image processing methods. This has revealed novel properties of FtsZ. The GTPase of archaeal FtsZ polymers is suppressed in Na ؉containing buffer, generating stabilized structures that require GDP addition for disassembly. FtsZ assembly is polymorphic. Archaeal FtsZ(wt) assembles into associated and isolated filaments made of two parallel protofilaments with a 43 Å longitudinal spacing between monomers, and this structure is also observed in bacterial FtsZ from Escherichia coli. The His 6 extension facilitates the artificial formation of helical tubes and sheets. FtsZ-W319Y-His 6 is an inactivated GTPase whose assembly remains regulated by GTP and Mg 2؉ . It forms twodimensional crystals made of symmetrical pairs of tubulin-like protofilaments, which associate in an antiparallel array (similarly to the known Ca 2؉ -induced sheets of FtsZ-His 6 ). In contrast to the lateral interactions of microtubule protofilaments, we propose that the primary assembly product of FtsZ is the double-stranded filament, one or several of which might form the dynamic Z ring during prokaryotic cell division.
Arthroscopy-the Journal of Arthroscopic and Related Surgery, 2001
We present the case of a 16-year-old boy with an 18-month history of pain in the left groin for 1... more We present the case of a 16-year-old boy with an 18-month history of pain in the left groin for 18 months. In addition to the simple radiographic examination, magnetic resonance imaging, bone scan, and computed tomography were necessary to finally diagnose an acetabulum osteoid osteoma (AOO). Excision of the lesion was performed arthroscopically and pathologic testing confirmed the diagnosis. The patient's symptoms disappeared immediately after the surgery, and had not reappeared as of the 6-month postoperative evaluation. We conclude that arthroscopic excision of an AOO is possible and avoids the aggressive open approach as well as operative hip dislocation.
We have studied the assembly and GTPase of purified FtsZ from the hyperthermophilic archaeon Meth... more We have studied the assembly and GTPase of purified FtsZ from the hyperthermophilic archaeon Methanococcus jannaschii, a structural homolog of eukaryotic tubulin, employing wild-type FtsZ, FtsZ-His 6 (histidinetagged FtsZ), and the new mutants FtsZ-W319Y and FtsZ-W319Y-His 6 , with light scattering, nucleotide analyses, electron microscopy, and image processing methods. This has revealed novel properties of FtsZ. The GTPase of archaeal FtsZ polymers is suppressed in Na ؉containing buffer, generating stabilized structures that require GDP addition for disassembly. FtsZ assembly is polymorphic. Archaeal FtsZ(wt) assembles into associated and isolated filaments made of two parallel protofilaments with a 43 Å longitudinal spacing between monomers, and this structure is also observed in bacterial FtsZ from Escherichia coli. The His 6 extension facilitates the artificial formation of helical tubes and sheets. FtsZ-W319Y-His 6 is an inactivated GTPase whose assembly remains regulated by GTP and Mg 2؉ . It forms twodimensional crystals made of symmetrical pairs of tubulin-like protofilaments, which associate in an antiparallel array (similarly to the known Ca 2؉ -induced sheets of FtsZ-His 6 ). In contrast to the lateral interactions of microtubule protofilaments, we propose that the primary assembly product of FtsZ is the double-stranded filament, one or several of which might form the dynamic Z ring during prokaryotic cell division.
Arthroscopy-the Journal of Arthroscopic and Related Surgery, 2001
We present the case of a 16-year-old boy with an 18-month history of pain in the left groin for 1... more We present the case of a 16-year-old boy with an 18-month history of pain in the left groin for 18 months. In addition to the simple radiographic examination, magnetic resonance imaging, bone scan, and computed tomography were necessary to finally diagnose an acetabulum osteoid osteoma (AOO). Excision of the lesion was performed arthroscopically and pathologic testing confirmed the diagnosis. The patient's symptoms disappeared immediately after the surgery, and had not reappeared as of the 6-month postoperative evaluation. We conclude that arthroscopic excision of an AOO is possible and avoids the aggressive open approach as well as operative hip dislocation.
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Papers by Juan Palacios