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Oliveira, R. J.

Publications and source records attributed to Oliveira, R. J..

2 recordsLinked to original sources

Asynchronous structural rearrangements govern constriction of the human nuclear pore complex

The nuclear pore complex (NPC) is responsible for transport between the cytoplasm and nucleus. CryoET experiments have resolved multiple conformations of the pore that are dilated or constricted. Since the dilation state will impact transport properties, there is much interest in understanding the energetic factors that regulate dilation/constriction. To this end, we applied a structure-based (G[o]-like) model to study the mechanistic properties of large-scale constriction ( [~] 100[A]) in the human NPC. Even though the structures are symmetric, the simulations implicate asynchronous rear-rangements during constriction. By considering variants of the model, we further characterize the relative contributions of individual proteins to this collective process. Together, this provides an energetic/structural foundation that can guide development of precise physical approaches for studying this elusive motion.

biophysics↗

Organometallic gold(III) Cl (L1 = SNS-donating thiosemicarbazone) complex protects mice against acute T. cruzi infection

Chagas disease remains a serious public health concern with unsatisfactory treatment outcomes due to strain-specific drug resistance and various side effects. To identify new therapeutic drugs against Trypanosoma cruzi, we evaluated both the in vitro and in vivo activity of the organometallic gold(III) complex [Au(Hdamp)(L14)]Cl (L1 = SNS- donating thiosemicarbazone), which was denoted 4-Cl. Our results demonstrated that 4- Cl was more effective than benznidazole (Bz) in eliminating both the extracellular trypomastigote and the intracellular amastigote forms of the parasite without cytotoxic effects on mammalian cells. In very-low-dose in vivo assays, 4-Cl reduced parasitaemia and tissue parasitism in addition to protecting the liver and heart from tissue damage. All these changes resulted in the survival of 100% of the mice treated with 4-Cl during the acute phase. We hypothesised that 4-Cl can act directly on the parasite and may participate in the modulation of IFN-{gamma} production at the acute stage of the disease. Molecular docking simulations showed that the compound may interact with cruzain, a thiol protease considered a possible antiparasitic drug target, primarily by hydrophobic interactions. These analyses predicted that the Cys25 residue in the cruzain binding site is approximately 3.0 [A] away from the S and Au atoms of the gold compound, which could suggest formation of a possible covalent bond between cruzain and the inhibitor. Overall, we confirmed the potential of 4-Cl as a new candidate for Chagas disease treatment.

pharmacology and toxicology↗