Banca de DEFESA: GRACIANNY GOMES MARTINS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : GRACIANNY GOMES MARTINS
DATA : 12/11/2019
HORA: 08:30
LOCAL: programa de Biologia Experimental
TÍTULO:

Identificação de um peptídeo derivado de uma metaloprotease de Bothrops moojeni com ação inibitória in vitro sobre uma enzima fosforilase de nucleosídeos puros de Plasmodium falciparum (PfPNP).

PALAVRAS-CHAVES:

Keywords: Malaria, Plasmodium falciparum, Purine Nucleoside Phosphorylase, Snake Venom, Metalloprotease.

PÁGINAS: 90
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

There is a growing need for research on new antimalarial agents for Plasmodium falciparum infection, based mainly on rational drug planning for specific molecular targets in the parasite, as the emergence of resistance to most drugs for malaria treatment has been widely reported. reported. Therefore, the general objective of this study was to evaluate the activity of a metalloprotease of Bothrops moojeni (BmooMPα-I) against Plasmodium falciparum in vitro and by in silico studies, to map and identify for the first time peptide regions with potential inhibitory action. of P. falciparum purine nucleoside phosphorylase enzyme (PfPNP), an enzyme necessary for parasite survival. BmooMPα-I was initially isolated by reverse phase and cation exchange chromatography, and then in vitro assays for antiparasitic activity against P. falciparum W2 strain were performed. For in silico assays, the interactions between BmooMPα-I and PfPNP were evaluated via molecular docking and the resulting peptide, called Pep 1 BM, was selected according to the region of BmooMPα-I with the best interaction target with the target. interest. The values for specific PfPNP reaction activities were measured using the inorganic phosphate substrate and MESG. The fraction corresponding to BmooMPα-I was identified as fraction 4 in the cation exchange chromatography step, due to proteolytic activity on casein and the presence of a 23 kDa main band. BmooMPα-I was able to inhibit in vitro growth of P. falciparum W2, with an IC50 value of 16.14 µg / mL. Pep1 BM virtual screening demonstrated two binding regions with the PfPNP target, with ∆G values at the interaction interface of -10.75 kcal / mol and -11.74 kcal / mol. Multiple alignment analysis of class PI snake metalloprotease sequences with Pep 1 BM peptide demonstrated that this region is not conserved in other species. A significant reduction in PfPNP enzymatic activity was noted due to the presence of Pep 1 BM when compared to the in vitro activity assay of this enzyme in the absence of this possible inhibitor. When evaluating the in vitro antiparasitic activity of the peptide, an IC50 value of ≥ 200 µg / mL was observed, not showing significant in vitro activity against P. falciparum W2. The in silico techniques identified Pep 1 BM peptide with potential affinity binding to the PfPNP catalytic site and its ability to inhibit its enzymatic activity in vitro. Further studies of molecular modification are necessary to propose strategies that favor the physicochemical characteristics of the peptide, such as its hydro and liposolubility profile, molecular mass and ionization coefficient, in order to obtain a derivative capable of reproducing the inhibitory biological effect on the PfPNP target in in vitro experiments against P. falciparum This study provided perspectives for continuity of Pep 1 BM molecule assays and could be directed to the development of biologically active analogs that can have their activities improved through deletion, addition and rational modification of the amino acid sequence, allowing to expand molecular diversity and improve properties. to propose potential new therapies for the treatment of malaria.

MEMBROS DA BANCA:
Presidente - 004.161.386-40 - ANDREIMAR MARTINS SOARES - UNIFESP
Interno - 218.429.088-20 - CAROLINA BIONE GARCIA TELES - UNESP
Externo à Instituição - VIVIANE KROMINSKI GRAÇA DE SOUZA - São Lucas
Externo à Instituição - GEISA PAULINO CAPRINI EVARISTO - FIOCRUZ
Externo à Instituição - MARCOS ROBERTO DE MATTOS FONTES - UNESP
Externo à Instituição - RUDSON DE JESUS HOLANDA - UNIR
Externo à Instituição - SORAYA DOS SANTOS PEREIRA - FIOCRUZ