Navegando por Orientadores "BARROS, Carlos Augusto Lima"

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Acesso aberto (Open Access)
Aspectos teóricos da interação entre compostos cefalosporínicos e a Proteína 5 de Ligação à Penicilina de Escherichia coli usando Dinâmica Molecular
(Universidade Federal do Pará, 2018-08-04) OLIVEIRA, Amanda Ruslana Santana; BARROS, Carlos Augusto Lima; http://lattes.cnpq.br/8902921733540173
Escherichia coli is an anaerobic Gram-negative bacillus that naturally inhabits the intestines of mammals. The diseases arise when the bacteria reaches other organs of our body, causing infections, mainly in the urinary tract of women, due to the proximity of the female urethra with the anus. Antibiotics were used in the treatment of these infections, such as antibiotics of the cephalosporin class, which are the group with the highest number of β-lactam antibiotics in clinical use. These compounds can inhibiting the enzymatic function of Penicillin-Binding Proteins (PBP), which is responsible for the final step of biosynthesis of peptidoglycan, an essential component for the survival of bacteria. In this work, the antimicrobial compounds cefoxitin, cefuroxime, cefotaxime, cephalothin, cefixime, cefmetazole and 7- aminocephalosporanic acid were chosen based on experimental studies of biological activity in the fight against the opportunistic Gram-negative pathogen Pseudomonas aeruginosa, to be studied theoretically through Molecular Dynamics simulations, binding free energy calculations, and interaction energy per residue, for the determination of their potential biological activity in inhibiting the enzymatic function of E. coli specific PBP, Penicillin Binding Protein 5 (PBP5), therefore its inhibition leads to cell death. More favorable binding free energies were obtained for the cefoxitin (crystallographic), cephalothin and cefuroxime ligands, -31.471 Kcal/mol, - 34.225 Kcal/mol and -35.085 Kcal/mol, respectively, and it was observed that the catalytic residues Ser44 and His216 presented more favorable energy contributions to the system formed by the cephalothin ligand. Thus, it was suggested that cephalothin has excellent potential for inhibition of the enzymatic function of E. coli PBP5, responsible for the final phase of transpeptidation of the peptidoglycan layer.
Acesso aberto (Open Access)
Usando a dinâmica molecular para avaliar o impacto que as mutações na protease do HIV-1 produzem na interação da proteína com o antirretroviral darunavir
(Universidade Federal do Pará, 2019-03-29) CUNHA, Karoline Leite; BARROS, Carlos Augusto Lima; http://lattes.cnpq.br/8902921733540173
The emergence of drug-resistant strains used in antiretroviral therapy grows alarmingly on a global scale. Antiretrovirals used in the treatment of first and second line HIV are the ones that most have case reports of resistant strains. Protease inhibitors are a class of antiretroviral drugs that play a key role in AIDS treatment regimens. In addition to the emergence of resistance to IPs used in the usual treatment regimens, Darunavir, a protease inhibitor used in therapeutic rescue treatment, is already reported in patients who already have failed initial treatment and proven resistance. The aim of this work is to evaluate, identify and quantify HIV-1 3UCB protease mutations, as well as to evaluate, through molecular dynamics simulations, the impact that mutations produce on the interaction of 3UCB and its darunavir ligand when compared to the native HIV-1 protease 4LL3 complexed to the same linker.The results obtained in this study showed that the 3UCB multi-resistant HIV-1 protease had a slightly more stable binding profile than the native HIV-1 protease complex 4LL3, with binding free energy results -68.77 and -64.62 kcal / mol, respectively.