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The circadian nature of mood and its dysfunction in affective disorders is well recognized, but the underlying molecular mechanisms are still unclear. Here, we show that the circadian nuclear receptor REV-ERBα, which is associated with bipolar disorder, impacts midbrain dopamine production and mood-related behavior in mice. Genetic deletion of the Rev-erbα gene or pharmacological inhibition of REV-ERBα activity in the ventral midbrain induced mania-like behavior in association with a central hyperdopaminergic state. Also, REV-ERBα repressed tyrosine hydroxylase (TH) gene transcription via competition with nuclear receptor-related 1 protein (NURR1), another nuclear receptor crucial for dopaminergic neuronal function, thereby driving circadian TH expression through a target-dependent antagonistic mechanism. In conclusion, we identified a molecular connection between the circadian timing system and mood regulation, suggesting that REV-ERBα could be targeting in the treatment of circadian rhythm-related affective disorders.
Assuntos
Afeto , Ritmo Circadiano , Dopamina/metabolismo , Mesencéfalo/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Proteínas Repressoras/metabolismo , Animais , Transtorno Bipolar/genética , Proteínas CLOCK/genética , Proteínas CLOCK/metabolismo , Histonas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transtornos do Humor/genética , Transtornos do Humor/metabolismo , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Ratos , Receptores Citoplasmáticos e Nucleares/genética , Proteínas Repressoras/genética , Transcrição Gênica , Tirosina 3-Mono-Oxigenase/genéticaRESUMO
A spinal cord injury interrupts pathways from the brain and brainstem that project to the lumbar spinal cord, leading to paralysis. Here we show that spatiotemporal epidural electrical stimulation (EES) of the lumbar spinal cord1-3 applied during neurorehabilitation4,5 (EESREHAB) restored walking in nine individuals with chronic spinal cord injury. This recovery involved a reduction in neuronal activity in the lumbar spinal cord of humans during walking. We hypothesized that this unexpected reduction reflects activity-dependent selection of specific neuronal subpopulations that become essential for a patient to walk after spinal cord injury. To identify these putative neurons, we modelled the technological and therapeutic features underlying EESREHAB in mice. We applied single-nucleus RNA sequencing6-9 and spatial transcriptomics10,11 to the spinal cords of these mice to chart a spatially resolved molecular atlas of recovery from paralysis. We then employed cell type12,13 and spatial prioritization to identify the neurons involved in the recovery of walking. A single population of excitatory interneurons nested within intermediate laminae emerged. Although these neurons are not required for walking before spinal cord injury, we demonstrate that they are essential for the recovery of walking with EES following spinal cord injury. Augmenting the activity of these neurons phenocopied the recovery of walking enabled by EESREHAB, whereas ablating them prevented the recovery of walking that occurs spontaneously after moderate spinal cord injury. We thus identified a recovery-organizing neuronal subpopulation that is necessary and sufficient to regain walking after paralysis. Moreover, our methodology establishes a framework for using molecular cartography to identify the neurons that produce complex behaviours.
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Neurônios , Paralisia , Traumatismos da Medula Espinal , Medula Espinal , Caminhada , Animais , Humanos , Camundongos , Neurônios/fisiologia , Paralisia/genética , Paralisia/fisiopatologia , Paralisia/terapia , Medula Espinal/citologia , Medula Espinal/fisiologia , Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/genética , Traumatismos da Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/terapia , Caminhada/fisiologia , Estimulação Elétrica , Região Lombossacral/inervação , Reabilitação Neurológica , Análise de Sequência de RNA , Perfilação da Expressão GênicaRESUMO
BACKGROUND: The optimal duration of dual antiplatelet therapy (DAPT) in patients with chronic kidney disease undergoing percutaneous coronary intervention (PCI), especially with third-generation drug-eluting stents (DES), remains unknown. METHODS AND RESULTS: We conducted a prespecified post hoc analysis of the HOST-IDEA trial, randomizing patients undergoing PCI with third-generation DES to 3- to 6-month or 12-month DAPT. In all, 1,997 patients were grouped by their estimated glomerular filtration rate (eGFR): high (>90 mL/min/1.73 m2), intermediate (60-90 mL/min/1.73 m2), and low (<60 mL/min/1.73 m2). The primary outcome was net adverse clinical events (NACE), a composite of cardiac death, target vessel myocardial infarction, clinically driven target lesion revascularization, stent thrombosis, or major bleeding (Bleeding Academic Research Consortium Type 3 or 5) at 12 months. Secondary outcomes were target lesion failure (TLF) and major bleeding. The low eGFR group had the highest rates of NACE, TLF, and major bleeding compared with the other 2 groups (P<0.001). Rates of NACE were similar in the 3- to 6-month and 12-month DAPT in the high (2.9% vs. 3.2%; P=0.84), intermediate (2.1% vs. 2.8%, P=0.51), and low (8.9% vs. 9.1%; hazard ratio 0.99; P=0.97; Pinteraction=0.88) eGFR groups. TLF and major bleeding events showed similar trends. CONCLUSIONS: In patients undergoing PCI with third-generation DES, 3- to 6-month DAPT was comparable to 12-month DAPT for clinical outcomes regardless of renal function.
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Allosteric integrase inhibitors (ALLINIs) are a class of experimental anti-HIV agents that target the noncatalytic sites of the viral integrase (IN) and interfere with the IN-viral RNA interaction during viral maturation. Here, we report a highly potent and safe pyrrolopyridine-based ALLINI, STP0404, displaying picomolar IC50 in human PBMCs with a >24,000 therapeutic index against HIV-1. X-ray structural and biochemical analyses revealed that STP0404 binds to the host LEDGF/p75 protein binding pocket of the IN dimer, which induces aberrant IN oligomerization and blocks the IN-RNA interaction. Consequently, STP0404 inhibits proper localization of HIV-1 RNA genomes in viral particles during viral maturation. Y99H and A128T mutations at the LEDGF/p75 binding pocket render resistance to STP0404. Extensive in vivo pharmacological and toxicity investigations demonstrate that STP0404 harbors outstanding therapeutic and safety properties. Overall, STP0404 is a potent and first-in-class ALLINI that targets LEDGF/p75 binding site and has advanced to a human trial.
Assuntos
Inibidores de Integrase de HIV/farmacologia , HIV-1/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Regulação Alostérica/efeitos dos fármacos , Animais , Cães , Infecções por HIV/tratamento farmacológico , Humanos , Ratos , Ratos Sprague-Dawley , Replicação Viral/efeitos dos fármacosRESUMO
Polyhydroxyalkanoates (PHAs) are diverse biopolyesters produced by numerous microorganisms and have attracted much attention as a substitute for petroleum-based polymers. Despite several decades of study, the detailed molecular mechanisms of PHA biosynthesis have remained unknown due to the lack of structural information on the key PHA biosynthetic enzyme PHA synthase. The recently determined crystal structure of PHA synthase, together with the structures of acetyl-coenzyme A (CoA) acetyltransferase and reductase, have changed this situation. Structural and biochemical studies provided important clues for the molecular mechanisms of each enzyme as well as the overall mechanism of PHA biosynthesis from acetyl-CoA. This new information and knowledge is expected to facilitate production of designed novel PHAs and also enhanced production of PHAs.
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Poli-Hidroxialcanoatos/metabolismo , Acetato-CoA Ligase/metabolismo , Acetil-CoA C-Acetiltransferase/metabolismo , Oxirredutases do Álcool/metabolismo , Catálise , Estrutura Molecular , Poli-Hidroxialcanoatos/química , Polimerização , Especificidade por SubstratoRESUMO
BACKGROUND: Statin treatment increases the risk of new-onset diabetes mellitus (NODM); however, data directly comparing the risk of NODM among individual statins is limited. We compared the risk of NODM between patients using pitavastatin and atorvastatin or rosuvastatin using reliable, large-scale data. METHODS: Data of electronic health records from ten hospitals converted to the Observational Medical Outcomes Partnership Common Data Model (n = 14,605,368 patients) were used to identify new users of pitavastatin, atorvastatin, or rosuvastatin (atorvastatin + rosuvastatin) for ≥ 180 days without a previous history of diabetes or HbA1c level ≥ 5.7%. We conducted a cohort study using Cox regression analysis to examine the hazard ratio (HR) of NODM after propensity score matching (PSM) and then performed an aggregate meta-analysis of the HR. RESULTS: After 1:2 PSM, 10,238 new pitavastatin users (15,998 person-years of follow-up) and 18,605 atorvastatin + rosuvastatin users (33,477 person-years of follow-up) were pooled from 10 databases. The meta-analysis of the HRs demonstrated that pitavastatin resulted in a significantly reduced risk of NODM than atorvastatin + rosuvastatin (HR 0.72; 95% CI 0.59-0.87). In sub-analysis, pitavastatin was associated with a lower risk of NODM than atorvastatin or rosuvastatin after 1:1 PSM (HR 0.69; CI 0.54-0.88 and HR 0.74; CI 0.55-0.99, respectively). A consistently low risk of NODM in pitavastatin users was observed when compared with low-to-moderate-intensity atorvastatin + rosuvastatin users (HR 0.78; CI 0.62-0.98). CONCLUSIONS: In this retrospective, multicenter active-comparator, new-user, cohort study, pitavastatin reduced the risk of NODM compared with atorvastatin or rosuvastatin.
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Diabetes Mellitus , Inibidores de Hidroximetilglutaril-CoA Redutases , Atorvastatina/efeitos adversos , Estudos de Coortes , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/epidemiologia , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Estudos Multicêntricos como Assunto , Quinolinas , Estudos Retrospectivos , Rosuvastatina Cálcica/efeitos adversosRESUMO
Cupriavidus necator H16 is a gram-negative chemolithoautotrophic bacterium that has been extensively studied for biosynthesis and biodegradation of polyhydroxyalkanoate (PHA) plastics. To improve our understanding of fatty acid metabolism for PHA production, we determined the crystal structure of multi-functional enoyl-CoA hydratase from Cupriavidus necator H16 (CnFadB). The predicted model of CnFadB created by AlphaFold was used to solve the phase problem during determination of the crystal structure of the protein. The CnFadB structure consists of two distinctive domains, an N-terminal enol-CoA hydratase (ECH) domain and a C-terminal 3-hydroxyacyl-CoA dehydrogenase (HAD) domain, and the substrate- and cofactor-binding modes of these two functional domains were identified. Unlike other known FadB enzymes that exist as dimers complexed with FadA, CnFadB functions as a monomer without forming a complex with CnFadA. Small angle X-ray scattering (SAXS) measurement further proved that CnFadB exists as a monomer in solution. The non-sequential action of FadA and FadB in C. necator appears to affect ß-oxidation and PHA synthesis/degradation.
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Cupriavidus necator , Poli-Hidroxialcanoatos , Cupriavidus necator/metabolismo , Poli-Hidroxialcanoatos/metabolismo , Espalhamento a Baixo Ângulo , Difração de Raios X , Enoil-CoA Hidratase/metabolismo , Ácidos Graxos/metabolismo , Plásticos/metabolismo , 3-Hidroxiacil-CoA Desidrogenase/metabolismo , Coenzima A/metabolismoRESUMO
The circadian clock is a self-sustaining oscillator that controls daily rhythms. For the proper circadian gene expression, dynamic changes in chromatin structure are important. Although chromatin modifiers have been shown to play a role in circadian gene expression, the in vivo role of circadian signal-modulated chromatin modifiers at an organism level remains to be elucidated. Here, we provide evidence that the lysine-specific demethylase 1 (LSD1) is phosphorylated by protein kinase Cα (PKCα) in a circadian manner and the phosphorylated LSD1 forms a complex with CLOCK:BMAL1 to facilitate E-box-mediated transcriptional activation. Knockin mice bearing phosphorylation-defective Lsd1(SA/SA) alleles exhibited altered circadian rhythms in locomotor behavior with attenuation of rhythmic expression of core clock genes and impaired phase resetting of circadian clock. These data demonstrate that LSD1 is a key component of the molecular circadian oscillator, which plays a pivotal role in rhythmicity and phase resetting of the circadian clock.
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Ritmo Circadiano , Regulação da Expressão Gênica , Oxirredutases N-Desmetilantes/metabolismo , Proteína Quinase C-alfa/metabolismo , Fatores de Transcrição ARNTL/metabolismo , Sequência de Aminoácidos , Animais , Comportamento Animal , Proteínas CLOCK/metabolismo , Imunoprecipitação da Cromatina , Histona Desmetilases , Luz , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Dados de Sequência Molecular , Oscilometria , Oxirredutases N-Desmetilantes/genética , Fosforilação , Regiões Promotoras Genéticas , Homologia de Sequência de Aminoácidos , Núcleo Supraquiasmático/metabolismo , Fatores de TempoRESUMO
The coding gene for peptidoglycan editing factor (pdeF) is located in the division and cell wall (dcw) cluster, and encodes a protein that has an editing function for misplaced amino acids in peptidoglycan in E. coli. In this study, we determined the crystal structure of PdeF from Bacillus cereus (BcPdeF) at a 1.60 Å resolution. BcPdeF exists as a monomer in solution and consists of two domains: a core domain containing a Pfam motif DUF152 and a smaller subdomain. The X-ray fluorescence spectrum of BcPdeF crystal elucidated that the protein has a Zn2+ ion in its active site and the metal ion was coordinated by two histidine and one cysteine residue. We also performed docking calculations of the N-acetylmuramate (MurNAc)-L-Ser-D-iGlu ligand in the BcPdeF structure and revealed the substrate binding mode of the enzyme. Furthermore, structural comparisons between BcPdeF and human fatty acid metabolism-immunity nexus (FAMIN), which also contains the DUF152 motif in its core domain, provided a structural basis how the two structurally similar proteins have completely different physiological functions.
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Flexible and soft bioelectronics display conflicting demands on miniaturization, compliance, and reliability. Here, the authors investigate the design and performance of thin encapsulation multilayers against hermeticity and mechanical integrity. Partially cracked organic/inorganic multilayer coatings are demonstrated to display surprisingly year-long hermetic lifetime under demanding mechanical and environmental loading. The thin hermetic encapsulation is grown in a single process chamber as a continuous multilayer with dyads of atomic layer deposited (ALD) Al2 O3 -TiO2 and chemical vapor deposited Parylene C films with strong interlayer adhesion. Upon tensile loading, tortuous diffusion pathways defined along channel cracks in the ALD oxide films and through tough Parylene films efficiently postpone the hermeticity failure of the partially cracked coating. The authors assessed the coating performance against prolonged exposure to biomimetic physiological conditions using coated magnesium films, platinum interdigitated electrodes, and optoelectronic devices prepared on stretchable substrates. Designed extension of the lifetime preventing direct failures reduces from over 5 years yet tolerates the lifetime of 3 years even with the presence of critical damage, while others will directly fail less than two months at 37 °C. This strategy should accelerate progress on thin hermetic packaging for miniaturized and compliant implantable electronics.
Assuntos
Óxido de Alumínio , Próteses e Implantes , Eletrodos , Eletrônica , Reprodutibilidade dos TestesRESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19) pandemic. The virus still spreads globally through human-to-human transmission. Nevertheless, there are no specific treatments clinically approved. This study aimed to compare antiviral activity of gemcitabine and its analogue 2'-fluoro-2'-deoxycytidine (2FdC) against SARS-CoV-2 as well as cytotoxicity in vitro. Fluorescent image-based antiviral assays revealed that gemcitabine was highly potent, with a 50% effective concentration (EC50) of 1.2 µM, more active than the well-known nucleoside monophosphate remdesivir (EC50 = 35.4 µM). In contrast, 2FdC was marginally active (EC50 = 175.2 µM). For all three compounds, the 50% cytotoxic concentration (CC50) values were over 300 µM toward Vero CCL-81 cells. Western blot and quantitative reverse-transcription polymerase chain reaction analyses verified that gemcitabine blocked viral protein expression in virus-infected cells, not only Vero CCL-81 cells but also Calu-3 human lung epithelial cells in a dose-dependent manner. It was found that gemcitabine has a synergistic effect when combined with remdesivir. This report suggests that the difluoro group of gemcitabine is critical for the antiviral activity and that its combination with other evaluated antiviral drugs, such as remdesivir, could be a desirable option to treat SARS-CoV-2 infection.
Assuntos
Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Tratamento Farmacológico da COVID-19 , Desoxicitidina/análogos & derivados , SARS-CoV-2/efeitos dos fármacos , Monofosfato de Adenosina/farmacologia , Alanina/farmacologia , Animais , Antivirais/farmacologia , COVID-19/metabolismo , COVID-19/virologia , Linhagem Celular , Chlorocebus aethiops , Desoxicitidina/farmacologia , Quimioterapia Combinada , Humanos , Concentração Inibidora 50 , SARS-CoV-2/fisiologia , Células Vero , Replicação Viral/efeitos dos fármacos , GencitabinaRESUMO
Fumarylacetoacetate hydrolase (FAH) superfamily proteins are found ubiquitously in microbial pathways involved in the catabolism of aromatic substances. Although extensive bioinformatic data on these proteins have been acquired, confusion caused by problems with the annotation of these proteins hinders research into determining their physiological functions. Here we classify 606 FAH superfamily proteins using a maximum likelihood (ML) phylogenetic tree, comparative gene-neighbourhood patterns and in vitro enzyme assays. The FAH superfamily proteins used for the analyses are divided into five distinct subfamilies, and two of them, FPH-A and FPH-B, contain the majority of the proteins of undefined function. These subfamilies include clusters designated FPH-I and FPH-II, respectively, which include two distinct types of fumarylpyruvate hydrolase (FPH), an enzyme involved in the final step of the gentisate pathway. We determined the crystal structures of these FPH enzymes at 2.0 Å resolutions and investigate the substrate binding mode by which these types of enzymes can accommodate fumarylpyruvate as a substrate. Consequentially, we identify the molecular signatures of the two types of FPH enzymes among the broadly conserved FAH superfamily proteins. Our studies allowed us to predict the relationship of unknown FAH superfamily proteins using their sequence information.
Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/classificação , Hidrolases/química , Hidrolases/classificação , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Hidrolases/genética , Hidrolases/metabolismo , FilogeniaRESUMO
The bi-functional malonyl-CoA reductase is a key enzyme of the 3-hydroxypropionate bi-cycle for bacterial CO2 fixation, catalysing the reduction of malonyl-CoA to malonate semialdehyde and further reduction to 3-hydroxypropionate. Here, we report the crystal structure and the full-length architecture of malonyl-CoA reductase from Porphyrobacter dokdonensis. The malonyl-CoA reductase monomer of 1230 amino acids consists of four tandemly arranged short-chain dehydrogenases/reductases, with two catalytic and two non-catalytic short-chain dehydrogenases/reductases, and forms a homodimer through paring contact of two malonyl-CoA reductase monomers. The complex structures with its cofactors and substrates revealed that the malonyl-CoA substrate site is formed by the cooperation of two short-chain dehydrogenases/reductases and one novel extra domain, while only one catalytic short-chain dehydrogenase/reductase contributes to the formation of the malonic semialdehyde-binding site. The phylogenetic and structural analyses also suggest that the bacterial bi-functional malonyl-CoA has a structural origin that is completely different from the archaeal mono-functional malonyl-CoA and malonic semialdehyde reductase, and thereby constitute an efficient enzyme.
Assuntos
Alphaproteobacteria/enzimologia , Malondialdeído/análogos & derivados , Malonil Coenzima A/metabolismo , Oxirredutases/metabolismo , Sítios de Ligação/fisiologia , Ácido Láctico/análogos & derivados , Ácido Láctico/metabolismo , Malondialdeído/metabolismo , Filogenia , Ligação Proteica/fisiologia , Conformação ProteicaRESUMO
Bacillus cereus ATCC 14579 is a known polyhydroxybutyrate (PHB)-producing microorganism that possesses genes associated with PHB synthesis such as PhaA, PhaB, and PHA synthases. PhaA (i.e., thiolase) is the first enzyme in the PHA biosynthetic pathway, which catalyze the condensation of two acetyl-CoA molecules to acetoacetyl-CoA. Our study elucidated the crystal structure of PhaA in Bacillus cereus ATCC 14579 (BcTHL) in its apo- and CoA-bound forms. BcTHL adopts a type II biosynthetic thiolase structure by forming a tetramer. The crystal structure of CoA-complexed BcTHL revealed that the substrate binding site of BcTHL is constituted by different residues compared with other known thiolases. Our study also revealed that Arg221, a residue involved in ADP binding, undergoes a positional conformational change upon the binding of the CoA molecule.
Assuntos
Acetil-CoA C-Acetiltransferase/química , Bacillus cereus/enzimologia , Proteínas de Bactérias/química , Domínio Catalítico , Coenzima A/química , Cristalografia por Raios X , Hidroxibutiratos/metabolismo , Modelos MolecularesRESUMO
Glycine oxidase (GO) is an enzyme that catalyzes the oxidation of the primary and secondary amines of various chemicals, including glycine, and the enzyme has been applied in a variety of fields, such as biosensor and genetically modified glyphosate resistance plants. Here, we report that the gene product of BC0747 from Bacillus cereus (BcGO) shows oxidase activity for glycine and small d-amino acids, such as d-proline and d-alanine. We also determined the crystal structure of BcGO complexed with the FAD cofactor at a 2.36 Å resolution and revealed how the cofactor binds to the deep pocket of the enzyme. We performed the molecular docking calculation of the glycine substrate to the BcGO structure and identified how the carboxyl- and amine-groups of the d-amino acid are stabilized at the substrate binding site. Structural analysis of BcGO also provided information on the structural basis for the stereospecificity of the enzyme to d-amino acids. In addition, we placed the glyphosate molecule, a plant herbicide, at the substrate binding site, and explained how the mutation of Gly51 to arginine enhances enzyme activity.
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Aminoácido Oxirredutases/química , Aminoácidos/química , Bacillus cereus/enzimologia , Aminoácido Oxirredutases/metabolismo , Aminoácidos/metabolismo , Domínio Catalítico , Flavina-Adenina Dinucleotídeo/química , Glicina/análogos & derivados , Glicina/química , Glicina/metabolismo , Cinética , Modelos Moleculares , Ligação Proteica , Estereoisomerismo , GlifosatoRESUMO
Methylobacterium extorquens is a methylotroph model organism that has the ability to assimilate formate using the tetrahydrofolate (THF) pathway. The formate-tetrahydrofolate ligase from M. extorquens (MeFtfL) is an enzyme involved in the THF pathway that catalyzes the conversion of formate, THF, and ATP into formyltetrahydrofolate and ADP. To investigate the biochemical properties of MeFtfL, we evaluated the metal usage and enzyme kinetics of the enzyme. MeFtfL uses the Mg ion for catalytic activity, but also has activity for Mn and Ca ions. The enzyme kinetics analysis revealed that Km value of farmate was much higher than THF and ATP, which shows that the ligation activity of MeFtfL is highly dependent on formation concentration. We also determined the crystal structure of MeFtfL at 2.8 Å resolution. MeFtfL functions as a tetramer, and each monomer consists of three domains. The structural superposition of MeFtfL with FtfL from Moorella thermoacetica allowed us to predict the substrate binding site of the enzyme.
Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Formiato-Tetra-Hidrofolato Ligase/química , Formiato-Tetra-Hidrofolato Ligase/metabolismo , Methylobacterium extorquens/enzimologia , Proteínas de Bactérias/genética , Domínio Catalítico , Cristalografia por Raios X , Formiato-Tetra-Hidrofolato Ligase/genética , Formiatos/metabolismo , Cinética , Redes e Vias Metabólicas , Methylobacterium extorquens/genética , Modelos Moleculares , Domínios e Motivos de Interação entre Proteínas , Estrutura Quaternária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
The glyoxylate cycle is an important anabolic pathway and acts under a C2 compound (such as acetic acid) rich condition in bacteria. The isocitrate lyase (ICL) enzyme catalyzes the first step in the glyoxylate cycle, which is the cleavage of isocitrate to glyoxylate and succinate. This enzyme is a metalo-enzyme that contains an Mg2+ or a Mn2+ion at the active site for enzyme catalysis. We expressed and purified ICL from Bacillus cereus (BcICL) and investigated its biochemical properties and metal usage through its enzyme activity and stability with various divalent metal ion. Based on the results, BcICL mainly utilized the Mg2+ ion for enzyme catalysis as well as the Mn2+, Ni2+ and Co2+ ions. To elucidate its molecular mechanisms, we determined the crystal structure of BcICL at 1.79 Å. Through this structure, we analyzed a tetrameric interaction of the protein. We also determined the BcICL structure in complex with both the metal and its products, glyoxylate and succinate at 2.50 Å resolution and revealed each ligand binding modes.
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Bacillus cereus/enzimologia , Isocitrato Liase/química , Domínio Catalítico , Cristalografia por Raios X , Glioxilatos/química , Isocitrato Liase/metabolismo , Magnésio/química , Metais/química , Modelos Moleculares , Multimerização Proteica , Alinhamento de Sequência , Análise de Sequência de Proteína , Ácido Succínico/químicaRESUMO
In this paper, we propose a new system for a real-time holographic augmented reality (AR) video service based on a photorealistic three-dimensional (3D) object point for multiple users to use simultaneously at various locations and viewpoints. To observe the object from all viewpoints, a camera system capable of acquiring the 3D volume of a real object is developed and is used to generate a real object in real-time. Using the normal of the object point, the observable points are mapped to the viewpoint at which the user is located, and a hologram based on the object point is generated. The angle at which the reflected light from each point is incident on the hologram plane is calculated, and the intensity of the interference light is adjusted according to the angle to generate a hologram with a higher 3D effect. The generated hologram is transmitted to each user to provide a holographic AR service. The entire system consists of a camera system comprising eight RGB-D (depth) cameras and two workstations for photorealistic 3D volume and hologram generation. Using this technique, a realistic hologram was generated. Through experiments displaying holograms simultaneously from several different viewpoints, it is confirmed that multiple users can concurrently receive hologram AR.
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In this paper, we propose a new method for coding a full complex hologram with random phase. Since holograms with random phase have very unique spatial and frequency characteristics, a new compression method suitable for such holograms is required. We analyze the frequency characteristics of holograms with random phases and propose a new adaptive discrete wavelet transform (aDWT). Next, we propose a new modified zerotree alogrithm (mZTA) suitable for the subband configuration generated by the modified wavelet transform method. The results of the compression using the proposed method showed higher efficiency than the previous method, and the reconstructed images showed visually superior results.
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INTRODUCTION: Synchronous and pulsatile neural activation of kisspeptin neurons in the arcuate nucleus (ARN) are important components of the gonadotropin-releasing hormone pulse generator, the final common pathway for central regulation of mammalian reproduction. However, whether ARN kisspeptin neurons can intrinsically generate self-sustained synchronous oscillations from the early neonatal period and how they are regulated remain unclear. OBJECTIVE: This study aimed to examine the endogenous rhythmicity of ARN kisspeptin neurons and its neural regulation using a neonatal organotypic slice culture model. METHODS: We monitored calcium (Ca2+) dynamics in real-time from individual ARN kisspeptin neurons in neonatal organotypic explant cultures of Kiss1-IRES-Cre mice transduced with genetically encoded Ca2+ indicators. Pharmacological approaches were employed to determine the regulations of kisspeptin neuron-specific Ca2+ oscillations. A chemogenetic approach was utilized to assess the contribution of ARN kisspeptin neurons to the population dynamics. RESULTS: ARN kisspeptin neurons in neonatal organotypic cultures exhibited a robust synchronized Ca2+ oscillation with a period of approximately 3 min. Kisspeptin neuron-specific Ca2+ oscillations were dependent on voltage-gated sodium channels and regulated by endoplasmic reticulum-dependent Ca2+ homeostasis. Chemogenetic inhibition of kisspeptin neurons abolished synchronous Ca2+ oscillations, but the autocrine actions of the neuropeptides were marginally effective. Finally, neonatal ARN kisspeptin neurons were regulated by N-methyl-D-aspartate and gamma-aminobutyric acid receptor-mediated neurotransmission. CONCLUSION: These data demonstrate that ARN kisspeptin neurons in organotypic cultures can generate synchronized and self-sustained Ca2+ oscillations. These oscillations controlled by multiple regulators within the ARN are a novel ultradian rhythm generator that is active during the early neonatal period.