RESUMO
Staphylococcus aureus hibernation promoting factor (SaHPF) is responsible for the formation of 100S ribosome dimers, which in turn help this pathogen to reduce energy spent under unfavorable conditions. Ribosome dimer formation strongly depends on the dimerization of the C-terminal domain of SaHPF (CTDSaHPF). In this study, we solved the crystal structure of CTDSaHPF at 1.6â¯Å resolution and obtained a precise arrangement of the dimer interface. Residues Phe160, Val162, Thr171, Ile173, Tyr175, Ile185 andThr187 in the dimer interface of SaHPF protein were mutated and the effects were analyzed for the formation of 100S disomes of ribosomes isolated from S. aureus. It was shown that substitution of any of single residues Phe160, Val162, Ile173, Tyr175 and Ile185 in the SaHPF homodimer interface abolished the ribosome dimerization in vitro.
Assuntos
Proteínas de Bactérias/genética , Proteínas Ribossômicas/genética , Ribossomos/genética , Infecções Estafilocócicas/genética , Staphylococcus aureus/ultraestrutura , Proteínas de Bactérias/química , Proteínas de Bactérias/ultraestrutura , Microscopia Crioeletrônica , Dimerização , Hibernação/genética , Humanos , Ligação Proteica/genética , Proteínas Ribossômicas/química , Proteínas Ribossômicas/ultraestrutura , Ribossomos/ultraestrutura , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/patogenicidadeRESUMO
Here we report the fabrication of magnetically responsive calcium carbonate microcrystals produced by coprecipitation of calcium carbonate in the presence of citrate-stabilized iron oxide nanoparticles. We demonstrate that the calcite microcrystals obtained possess superparamagnetic properties due to incorporated magnetite nanoparticles and can be manipulated by an external magnetic field. The microcrystals doped with magnetic nanoparticles were utilized as templates for the fabrication of hollow polyelectrolyte microcapsules, which retain the magnetic properties of the sacrificial cores and might be spatially manipulated using a permanent magnet, thus providing the magnetic-field-facilitated delivery and separation of materials templated on magnetically responsive calcite microcrystals.
