Estudo estrutural e comparativo entre Sirtuínas 2 de diferentes espécies de Leishmania / Structural and comparative study between Sirtuins 2 of different species of Leishmania by means of Comparative Modeling and Molecular Dynamic

As leishmanioses são doenças negligenciadas que afetam mais de um bilhão e meio de pessoas ao redor do mundo, principalmente nos países em desenvolvimento, provocando grandes impactos socioeconômicos. Os fármacos disponíveis para o tratamento dessas doenças são ineficazes e apresentam graves efeitos adversos. O processo de pesquisa de novos fármacos envolve, entre outras coisas, a seleção de alvos bioquímicos essenciais para a sobrevivência e desenvolvimento do agente causador. Neste sentido, a Sirtuína 2, uma enzima epigenética com atividade hidrolase essencial para a sobrevivência dos parasitas do gênero Leishmania se apresenta como um alvo validado na busca de novos fármacos contra essas parasitoses. O planejamento de fármacos baseado na estrutura do receptor requer o conhecimento da estrutura tridimensional da proteína alvo. Desta forma, a elucidação estrutural e um estudo minucioso das Sirtuínas das várias espécies do gênero Leishmania apresenta-se como uma importante abordagem na aplicação desta estratégia na busca por agentes quimioterápicos. Até o momento, na família Trypanosomatidae, a única estrutura tridimensional resolvida experimentalmente de uma enzima Sirtuína 2 é a da espécie L. infantum. Assim, este trabalho aplicou a abordagem de Modelagem Comparativa utilizando o software Modeller na construção de modelos da Sir2rp1 das espécies L. infantum, L. major e L. braziliensis, cujas sequências de aminoácidos foram extraídas do banco de dados UNIProt. Os modelos construídos foram validados por meio da função de escore DOPE do Modeller e dos servidores PROCHECK, MolProbity e QMEAN, avaliando sua qualidade estereoquímica e seu enovelamento. Os ligantes naturais da enzima foram sobrepostos nos modelos construídos por alinhamento estrutural utilizando o software PyMol e os complexos validados foram submetidos a simulações de Dinâmica Molecular através do pacote GROMACS. Os complexos refinados foram então analisados por meio dos softwares PyMol e LigPlotPlus e dos pacotes GROMACS e gmx_MMPBSA, e foram estudados os sítios de ligação dos substratos e os resíduos de aminoácidos relevantes envolvidos em sua ligação e reconhecimento. A Modelagem Comparativa da Sirtuína 2 humana e seus homólogos das espécies L. infantum, L. major e L. braziliensis, as simulações de Dinâmica Molecular realizadas com os modelos enzimáticos construídos e validados complexados com seus ligantes naturais, os cálculos de energia de interação entre os modelos e seus substratos e o estudo estrutural comparativo realizado entre eles nos fornecem uma base teórica para a busca de novos inibidores da Sirtuína 2 que sejam mais seletivos e potentes contra as enzimas parasitárias, abrindo caminho para o desenvolvimento de candidatos a fármacos leishmanicidas mais seguros e eficazes

Leishmaniasis are neglected diseases that affect more than one and a half billion people around the world, mainly in developing countries, causing major socioeconomic impacts. The drugs available for the treatment of these diseases are ineffective and have serious adverse effects. The process of researching new drugs involves, among other things, the selection of biochemical targets essential for the survival and development of the causative agent. In this sense, Sirtuin 2, an epigenetic enzyme with hydrolase activity essential for the survival of parasites of the Leishmania genus, presents itself as a validated target in the search for new drugs against these parasites. Structure-Based Drug Design requires knowledge of the three-dimensional structure of the target protein. In this way, structural elucidation and a detailed study of Sirtuins from various species of the genus Leishmania presents itself as an important approach in the application of this strategy in the search for chemotherapeutic agents. To date, in the Trypanosomatidae family, the only experimentally resolved three-dimensional structure of a Sirtuin 2 enzyme is that of the species L. infantum. Thus, this work applied the Comparative Modeling approach using the Modeller software in the construction of Sir2rp1 models of the species L. infantum, L. major and L. braziliensis, whose amino acid sequences were retrieved from the UNIProt database. The constructed models were validated using Modeller's DOPE score function and the PROCHECK, MolProbity and QMEAN servers, evaluating their stereochemical quality and folding. The enzyme's natural ligands were superimposed on the built models by structural alignment using the PyMol software and the validated complexes were subjected to Molecular Dynamics simulations using the GROMACS package. The refined complexes were then analyzed using the PyMol and LigPlotPlus softwares and the GROMACS and gmx_MMPBSA packages, and the substrate binding sites and relevant amino acid residues involved in their binding and recognition were studied. The Comparative Modeling of human Sirtuin 2 and its homologues from the species L. infantum, L. major and L. braziliensis, the Molecular Dynamics simulations carried out with the constructed and validated enzymatic models complexed with their natural ligands, the interaction energy calculations between the models and their substrates and the comparative structural study carried out between them provide us with a theoretical basis for the search for new Sirtuin 2 inhibitors that are more selective and potent against the parasitic enzymes, paving the way for the development of safer and more effective leishmanicidal drug candidates

Some bis (3-(4-nitrophenyl)acrylamide derivatives: Synthesis, characterization, DFT, antioxidant, antimicrobial properties, molecular docking and molecular dynamics simulation studies-Supplemenntary data

Alzheimer's disease, which is a progressive neurologic disorder, is the most common form of dementia. Although there are various treatment options for Alzheimer’s disease, there is no definite treatment for this disease yet. In this study it was aimed to investigate the treatment potentials of three bis(3-(4-nitrophenyl)acrylamide) derivatives, two of which are known and one is new, for Alzheimer's disease. The study consists of three parts; in the first part of the study, synthesis and characterization studies of the investigated compounds were carried out. In the characterization of the compounds, IR, 1H-NMR, 13C-NMR, LC-MS and elemental analysis techniques were used. In the second part of the study, the compounds were investigated computationally with the assistance of various computational techniques including density functional theory (DFT) calculations, molecular docking and molecular dynamics simulations. In this part, binding free energy calculations were also performed on the investigated compounds. Results of computational studies showed that synthesized compounds interacted with AChE effectively and can be promising structures as AChE inhibitors. In the last part of the study, antioxidant and antimicrobial properties of the compounds were investigated. Antioxidant activities were determined by DPPH? and ABTS?? radical scavenging methods. According to the DPPH? test, the most active compound was found to be 2, while the most active compound was found to be 3 according to the ABTS? test, showing that these methods for antioxidant assay were not significantly correlated with each other. On the other hand, the results of the antimicrobial activity tests showed that compound 3 was the most active compound, which exhibited both antioxidant and antimicrobial activity.

Some bis (3-(4-nitrophenyl)acrylamide derivatives: Synthesis, characterization, DFT, antioxidant, antimicrobial properties, molecular docking and molecular dynamics simulation studies

Alzheimer's disease, which is a progressive neurologic disorder, is the most common form of dementia. Although there are various treatment options for Alzheimer’s disease, there is no definite treatment for this disease yet. In this study it was aimed to investigate the treatment potentials of three bis(3-(4-nitrophenyl)acrylamide) derivatives, two of which are known and one is new, for Alzheimer's disease. The study consists of three parts; in the first part of the study, synthesis and characterization studies of the investigated compounds were carried out. In the characterization of the compounds, IR, 1H-NMR, 13C-NMR, LC-MS and elemental analysis techniques were used. In the second part of the study, the compounds were investigated computationally with the assistance of various computational techniques including density functional theory (DFT) calculations, molecular docking and molecular dynamics simulations. In this part, binding free energy calculations were also performed on the investigated compounds. Results of computational studies showed that synthesized compounds interacted with AChE effectively and can be promising structures as AChE inhibitors. In the last part of the study, antioxidant and antimicrobial properties of the compounds were investigated. Antioxidant activities were determined by DPPH? and ABTS?? radical scavenging methods. According to the DPPH? test, the most active compound was found to be 2, while the most active compound was found to be 3 according to the ABTS? test, showing that these methods for antioxidant assay were not significantly correlated with each other. On the other hand, the results of the antimicrobial activity tests showed that compound 3 was the most active compound, which exhibited both antioxidant and antimicrobial activity.

Characterization of the ligand binding of PGRP-L in half-smooth tongue sole (Cynoglossus semilaevis) by molecular dynamics and free energy calculation

Background: Peptidoglycan (PGN) recognition proteins (PGRPs) are important pattern recognition receptors of the host innate immune system that are involved in the immune defense against bacterial pathogens. PGRPs have been characterized in several fish species. The PGN-binding ability is important for the function of PGRPs. However, the PGRP-PGN interaction mechanism in fish remains unclear. In the present study, the 3-D model of a long PGRP of half-smooth tongue sole (Cynoglossus semilaevis) (csPGRP-L), a marine teleost with great economic value, was constructed through the comparative modeling method, and the key amino acids involved in the interaction with Lys-type PGNs and Dap-type PGNs were analyzed by molecular dynamics and molecular docking methods. Results: csPGRP-L possessed a typical PGRP structure, consisting of five ß-sheets and four α-helices. Molecular docking showed that the van der Waals forces had a slightly larger contribution than Coulombic interaction in the csPGRP-L-PGN complex. Moreover, the binding energies of csPGRP-L-PGNs computed by MM-PBSA method revealed that csPGRP-L might selectively bind both types of MTP-PGNs and MPP-PGNs. In addition, the binding energy of each residue of csPGRP-L was also calculated, revealing that the residues involved in the interaction with Lys-type PGNs were different from that with Dap-type PGNs. Conclusions: The 3-D structure of csPGRP-L possessed typical PGRP structure and might selectively bind both types of MTP- and MPP-PGNs, which provided useful insights to understanding the functions of fish PGRPs.