Navegando por Orientadores "CARNEIRO, Agnaldo da Silva"

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Acesso aberto (Open Access)
Estudo teórico das interações entre inibidores da inha, enoil acp redutase do mycobacterium tuberculosis
(Universidade Federal do Pará, 2017-09-29) BAHIA, Jeann Ricardo da Costa; CARNEIRO, Agnaldo da Silva; http://lattes.cnpq.br/8915348778787525
Isoniazid is the oldest, cheapest and most effective synthetic prodrug of the first line of treatment for Tuberculosis. It should be activated by the Mycobacterium tuberculosis catalase-peroxidase, KatG, which produces an isonicotinoyl-NADH adduct, INNADH, which targets the M. tuberculosis Enoyl-ACP reductase protein, InhA, in order to disrupt the synthesis chain of mycolic acids. Resistance to isoniazid alone or in combination with other drugs is one of the most common forms of resistant tuberculosis and poses a threat to the control of this disease. In this context, triclosan (TCL) appears as an alternative inhibitor of the synthesis of mycolic acids, since it is also specific to InhA. This study aims to evaluate the interactions of inhibitors of InhA through Molecular Dynamics Simulation (DM) and propose possible new inhibitors for this enzyme. The system used in this work was captured from the database PDB, code 4TRO. Eight ligands, NADH, INNADH, and the TCL, P31, P41, P52, P61, P72 and P80 derivatives were evaluated. In the lower region of the active site of InhA were more frequent π charge stacks made by PHE41 and PHE97 with the ligands NADH, INADH, P80, P31, P72, however P41 made a hydrogen bond (LH) with PHE41. In the central region of the active site, residues such as A GLY96, SER20 and ILE21 did LH with NADH, INNADH, P31, P41 and P80. In relation to the upper region of the InhA site. The PHE149 performed EC-π with the INNADH and P41. Already in P31 was an LH with this residue and in P80 the energies are favorable for interaction. The free energies of each system presented in descending order are INNADH (-72,038 kcal / mol), P80 (-45,841 kcal / mol), NADH (- 41,463 kcal / mol), P41 (-40,178 kcal / mol), P31 (-30.614 kcal / mol), p52 (-19.475 kcal / mol) and P61 (-12.297 kcal / mol). These results highlight P80 and P41 as promising candidates for M. tuberculosis mycolic acid synthesis inhibitors, since being an energy profile is competitive with the values shown by NADH.
Acesso aberto (Open Access)
Investigação computacional de bromo-ariloxi-2-acetamida etil-benzimidazólicos como inibidores não-peptídicos da proteinase cruzaína de trypanosoma cruzi
(Universidade Federal do Pará, 2017-11-17) FERREIRA, Fábio Jorge de Nazaré; ALENCAR, Nelson Alberto Nascimento de; http://lattes.cnpq.br/3035968396241810; https://orcid.org/ 0000-0002-5763-7024; CARNEIRO, Agnaldo da Silva; http://lattes.cnpq.br/8915348778787525
Chagas’ disease is an infection caused by the Trypanosoma Cruzi flagellated protozoan transmitted by insects (gnat) known in Brazil as “barbeiro” (barber). In the Amazon region, studies have shown that oral contamination has been frequent. The only available drugs for the treatment of Chagas’ disease - Benzonidazole (Rochagan R , Roche) and Nifurtimox (Lampit R , Bayer) - have shown limited efficiency and severe side effects. Cruzain is an enzyme present at all stages of the life cycle of T. cruzi and is the most abundant of the family of papain cysteine proteases found in the parasite, being a promising enzymatic target for the design and development of inhibitors against the disease. Non-peptidic non covalently bound to the enzyme were synthesized and evaluated biologically in vitro and in vivo by Ferreira et al. (2014) analogs of the 8D (or B95) leader compound (crystallographic), yielding a series of active compounds, of which the most powerful are: 8K, 8L and 8R. This work investigated the potential interactions and energies of the cruzain (PDB code: 3KKU) complexed with these four ligands by means of computational tools in order to help elucidate their potential inhibition activity in this enzyme. The computational protocol (parameters, topologies, coordinates, minimizations, thermalizations and productions) was the same for each system. In the final stage of molecular dynamics (MD) production, each system was simulated for a period of 100 ns, to which the mean square deviation (RMSD) stability values of the enzyme and the marked change in 8L ligand conformation were analyzed. The quality of the simulation was also evaluated through potential, kinetic and total energy, volume and temperature graphs. Interactions of hydrogen bonds of the ligands with some amino acid residues belonging to the catalytic site were analyzed. The interaction between the ASP161 and the 8R ligand is emphasized, being ratified by the energy decomposition by residue showing that ASP161 has the best contribution. In terms of binding free energy, the ∆Gtotal follows the experimental trend, pointing the 8R ligand as the most favorable to the reaction having a theoretical value of -30.04kcal.mol−1. This spontaneity is ratified by means of the values obtained with the SIE method, whose theoretical value was -7.54 kcal.mol−1. The results of this work should favor the optimization of compound 8R or development of a series of analogs of this molecule in order to be used as a possible drug for the treatment of Chagas’ disease.