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Here, we report the draft sequence of Blautia luti strain DSM 14534T, originally isolated from human feces. This draft contains 74 contigs, comprising 3,718,760 bp with a G+C content of 42.87%. The annotated draft contains 3,338 coding sequences (CDSs) and 110 RNA genes.
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BACKGROUND: Isocitrate dehydrogenase 1 (IDH1) is a dimeric enzyme responsible for supplying the cell's nicotinamide adenine dinucleotide phosphate (NADPH) reserves via dehydrogenation of isocitrate (ICT) and reduction of NADP+. Mutations in position R132 trigger cancer by enabling IDH1 to produce D-2-hydroxyglutarate (2-HG) and reduce inhibition by ICT. Mutant IDH1 can be found as a homodimer or a heterodimer. OBJECTIVE: We propose a novel strategy to inhibit IDH1 R132 variants as a means not to decrease the concentration of 2-HG but to provoke a cytotoxic effect, as the cell malignancy at this point no longer depends on 2-HG. We aim to inhibit the activity of the mutant heterodimer to block the wild-type subunit. Limiting the NADPH reserves in a cancerous cell will enhance its susceptibility to the oxidative stress provoked by chemotherapy. METHODS: We performed a virtual screening using all US FDA-approved drugs to replicate the loss of inhibition of mutant IDH1 by ICT. We characterized our results based on molecular interactions and correlated them with the described phenotypes. RESULTS: We replicated the loss of inhibition by ICT in mutant IDH1. We identified 20 drugs with the potential to inhibit the heterodimeric isoform. Six of them are used in cancer treatment. CONCLUSIONS: We present 20 FDA-approved drugs with the potential to inhibit IDH1 wild-type activity in mutated cells. We believe this work may provide important insights into current and new approaches to dealing with IDH1 mutations. In addition, it may be used as a basis for additional studies centered on drugs presenting differential sensitivities to different IDH1 isoforms.
Assuntos
Antineoplásicos/química , Dasatinibe/química , Inibidores Enzimáticos/química , Isocitrato Desidrogenase/antagonistas & inibidores , Pirimidinas/química , Sulfonamidas/química , Compostos de Tosil/química , Sequência de Aminoácidos , Sítios de Ligação , Di-Hidroergotamina/química , Epirubicina/química , Expressão Gênica , Ensaios de Triagem em Larga Escala , Humanos , Indazóis , Indóis , Isocitrato Desidrogenase/química , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Simulação de Acoplamento Molecular , Mutação , Fenilcarbamatos , Pivampicilina/química , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Termodinâmica , Interface Usuário-ComputadorRESUMO
Farnesyl diphosphate synthase (FPPS) is a key enzyme responsible for the supply of isoprenoid precursors for several essential metabolites, including sterols, dolichols and ubiquinone. In Saccharomyces cerevisiae, FPPS catalyzes the sequential condensation of two molecules of isopentenyl diphosphate (IPP) with dimethylallyl diphosphate (DMAPP), producing geranyl diphosphate (GPP) and farnesyl diphosphate (FPP). Critical amino acid residues that determine product chain length were determined by a comparative study of strict GPP synthases versus strict FPPS. In silico ΔΔG, i.e. differential binding energy between a protein and two different ligands-of yeast FPPS mutants was evaluated, and F96, A99 and E165 residues were identified as key determinants for product selectivity. A99X variants were evaluated in vivo, S. cerevisiae strains carrying A99R and A99H variants showed significant differences on GPP concentrations and specific growth rates. The FPPS A99T variant produced unquantifiable amounts of FPP and no effect on GPP production was observed. Strains carrying A99Q, A99Y and A99K FPPS accumulated high amounts of DMAPP-IPP, with a decrease in GPP and FPP. Our results demonstrated the relevance of the first residue before FARM (First Aspartate Rich Motif) over substrate consumption and product specificity of S. cerevisiae FPPS in vivo. The presence of A99H significantly modified product selectivity and appeared to be relevant for GPP synthesis.
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Regulação Fúngica da Expressão Gênica , Geraniltranstransferase/química , Mutação Puntual , Saccharomyces cerevisiae/enzimologia , Terpenos/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Substituição de Aminoácidos , Sítios de Ligação , Difosfatos/metabolismo , Diterpenos/metabolismo , Geraniltranstransferase/genética , Geraniltranstransferase/metabolismo , Hemiterpenos/metabolismo , Cinética , Engenharia Metabólica , Simulação de Acoplamento Molecular , Compostos Organofosforados/metabolismo , Fosfatos de Poli-Isoprenil/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Saccharomyces cerevisiae/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Sesquiterpenos/metabolismo , Especificidade por Substrato , TermodinâmicaRESUMO
Biomimetics, or the use of principles of Nature for developing new materials, is a paradigm that could help Nanomedicine tremendously. One of the current challenges in Nanomedicine is the rational design of new efficient and safer gene carriers. Poly(amidoamine) (PAMAM) dendrimers are a well-known class of nanoparticles, extensively used as non-viral nucleic acid carriers, due to their positively charged end-groups. Yet, there are still several aspects that can be improved for their successful application in in vitro and in vivo systems, including their affinity for nucleic acids as well as lowering their cytotoxicity. In the search of new functional groups that could be used as new dendrimer-reactive groups, we followed a biomimetic approach to determine the amino acids with highest prevalence in protein-DNA interactions. Then we introduced them individually as terminal groups of dendrimers, generating a new class of nanoparticles. Molecular dynamics studies of two systems: PAMAM-Arg and PAMAM-Lys were also performed in order to describe the formation of complexes with DNA. Results confirmed that the introduction of amino acids as terminal groups in a dendrimer increases their affinity for DNA and the interactions in the complexes were characterized at atomic level. We end up by briefly discussing additional modifications that can be made to PAMAM dendrimers to turned them into promising new gene carriers.
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Biomimética , Dendrímeros/química , Técnicas de Transferência de Genes , Nanopartículas , Sobrevivência Celular , Simulação de Dinâmica MolecularRESUMO
Sensory modalities are essential for navigating through an ever-changing environment. From insects to mammals, transient receptor potential (TRP) channels are known mediators for cellular sensing. Chlamydomonas reinhardtii is a motile single-celled freshwater green alga that is guided by photosensory, mechanosensory, and chemosensory cues. In this type of alga, sensory input is first detected by membrane receptors located in the cell body and then transduced to the beating cilia by membrane depolarization. Although TRP channels seem to be absent in plants, C. reinhardtii possesses genomic sequences encoding TRP proteins. Here, we describe the cloning and characterization of a C. reinhardtii version of a TRP channel sharing key features present in mammalian TRP channels associated with sensory transduction. In silico sequence-structure analysis unveiled the modular design of TRP channels, and electrophysiological experiments conducted on Human Embryonic Kidney-293T cells expressing the Cr-TRP1 clone showed that many of the core functional features of metazoan TRP channels are present in Cr-TRP1, suggesting that basic TRP channel gating characteristics evolved early in the history of eukaryotes.
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Chlamydomonas/metabolismo , Canais Iônicos/metabolismo , Mamíferos/metabolismo , Canais de Potencial de Receptor Transitório/metabolismo , Animais , Linhagem Celular , Eletrofisiologia , HumanosRESUMO
Salmonella Typhimurium is the etiological agent of gastroenteritis in humans and enteric fever in mice. Inside these hosts, Salmonella must overcome hostile conditions to develop a successful infection, a process in which the levels of porins may be critical. Herein, the role of the Salmonella Typhimurium porin OmpD in the infection process was assessed for adherence, invasion and proliferation in RAW264.7 mouse macrophages and in BALB/c mice. In cultured macrophages, a ΔompD strain exhibited increased invasion and proliferation phenotypes as compared to its parental strain. In contrast, overexpression of ompD caused a reduction in bacterial proliferation but did not affect adherence or invasion. In the murine model, the ΔompD strain showed increased ability to survive and replicate in target organs of infection. The ompD transcript levels showed a down-regulation when Salmonella resided within cultured macrophages and when it colonized target organs in infected mice. Additionally, cultured macrophages infected with the ΔompD strain produced lower levels of reactive oxygen species, suggesting that down-regulation of ompD could favor replication of Salmonella inside macrophages and the subsequent systemic dissemination, by limiting the reactive oxygen species response of the host.
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Proteínas de Bactérias/metabolismo , Macrófagos/metabolismo , Porinas/metabolismo , Salmonelose Animal/metabolismo , Salmonella typhimurium/fisiologia , Animais , Proteínas de Bactérias/genética , Regulação para Baixo , Escherichia coli/metabolismo , Feminino , Interações Hospedeiro-Patógeno , Macrófagos/microbiologia , Camundongos Endogâmicos BALB C , Modelos Moleculares , Mutação , Porinas/genética , Espécies Reativas de Oxigênio/metabolismo , Salmonelose Animal/microbiologia , Salmonella typhimurium/patogenicidadeRESUMO
A semiempirical methodology to model the intra-phycocyanin and inter-phycocyanin fluorescence resonance energy-transfer (FRET) pathways in the rods of the phycobilisomes (PBSs) from Fremyella diplosiphon is presented. Using the Förster formulation of FRET and combining experimental data and PM3 calculation of the dipole moments of the aromatic portions of the chromophores, transfer constants between pairs of chromophores in the phycocyanin (PC) structure were obtained. Protein docking of two PC hexamers was used to predict the optimal distance and axial rotation angle for the staked PCs in the PBSs' rods. Using the distance obtained by the docking process, transfer constants between pairs of chromophores belonging to different PC hexamers were calculated as a function of the angle of rotation. We show that six preferential FRET pathways within the PC hexameric ring and 15 pathways between hexamers exist, with transfer constants consistent with experimental results. Protein docking predicted the quaternary structure for PCs in rods with inter-phycocyanin distance of 55.6 A and rotation angle of 20.5 degrees . The inter-phycocyanin FRET constant between chromophores at positions beta(155) is maximized at the rotation angle predicted by docking revealing the crucial role of this specific inter-phycocyanin channel in defining the complete set of FRET pathways in the system.
Assuntos
Ficobilissomas/química , Ficocianina/química , Transferência Ressonante de Energia de Fluorescência , Modelos Moleculares , Conformação MolecularRESUMO
Phycocyanin is a phycobiliprotein involved in light harvesting and conduction of light to the reaction centers in cyanobacteria and red algae. The structure of C-phycocyanin from Gracilaria chilensis was solved by X-ray crystallography at 2.0 A resolution in space group P2(1). An interaction model between two PC heterohexamers was built, followed by molecular dynamic refinement. The best model showed an inter-hexamer rotation of 23 degrees . The coordinates of a PC heterohexamer (alphabeta)(6) and of the PC-PC complex were used to perform energy transfer calculations between chromophores pairs using the fluorescence resonance energy transfer approach (FRET). Two main intra PC ((I)beta(3)(82)-->(I)alpha(1)(84)-->(I)alpha(5)(84)-->(I)beta(6)(82) and (I)beta(3)(153)-->(I)beta(5)(153)) and two main inter PC ((I)beta(6)(82)-->(II)beta(3)(82) and (I)beta(5)(153)-->(II)beta(3)(153)) pathways were proposed based on the values of the energy transfer constants calculated for all the chromophore pairs in the hexamer and in the complex.