RESUMO
The aerobic oxidation of carbon monoxide to carbon dioxide is catalysed by the Mo/Cu-containing CO-dehydrogenase enzyme in the soil bacterium Oligotropha carboxidovorans, enabling the organism to grow on the small gas molecule as carbon and energy source. It was shown experimentally that silver can be substituted for copper in the active site of Mo/Cu CODH to yield a functional enzyme. In this study, we employed QM/MM calculations to investigate whether the reaction mechanism of the silver-substituted enzyme is similar to that of the native enzyme. Our results suggest that the Ag-substituted enzyme can oxidize CO and release CO2 following the same reaction steps as the native enzyme, with a computed rate-limiting step of 10.4â kcal/mol, consistent with experimental findings. Surprisingly, lower activation energies for C-O bond formation have been found in the presence of silver. Furthermore, comparison of rate constants for reduction of copper- and silver-containing enzymes suggests a discrepancy in the transition state stabilization upon silver substitution. We also evaluated the effects that differences in the water-active site interaction may exert on the overall energy profile of catalysis. Finally, the formation of a thiocarbonate intermediate along the catalytic pathway was found to be energetically unfavorable for the Ag-substituted enzyme. This finding aligns with the hypothesis proposed for the wild-type form, suggesting that the creation of such species may not be necessary for the enzymatic catalysis of CO oxidation.
Assuntos
Aldeído Oxirredutases , Monóxido de Carbono , Cobre , Molibdênio , Complexos Multienzimáticos , Oxirredução , Prata , Cobre/química , Cobre/metabolismo , Prata/química , Monóxido de Carbono/química , Monóxido de Carbono/metabolismo , Molibdênio/química , Molibdênio/metabolismo , Complexos Multienzimáticos/química , Complexos Multienzimáticos/metabolismo , Aldeído Oxirredutases/química , Aldeído Oxirredutases/metabolismo , Teoria QuânticaRESUMO
AIMS: Neocosmospora species are saprobes, endophytes, and pathogens belonging to the family Nectriaceae. This study aims to investigate the taxonomy, biosynthetic potential, and application of three newly isolated Neocosmospora species from mangrove habitats in the southern part of Thailand using phylogeny, bioactivity screening, genome sequencing, and bioinformatics analysis. METHODS AND RESULTS: Detailed descriptions, illustrations, and a multi-locus phylogenetic tree with large subunit ribosomal DNA (LSU), internal transcribed spacer (ITS), translation elongation factor 1-alpha (ef1-α), and RNA polymerase II second largest subunit (RPB2) regions showing the placement of three fungal strains, MFLUCC 17-0253, MFLUCC 17-0257, and MFLUCC 17-0259 clustered within the Neocosmospora clade with strong statistical support. Fungal crude extracts of the new species N. mangrovei MFLUCC 17-0253 exhibited strong antifungal activity to control Colletotrichum truncatum CG-0064, while N. ferruginea MFLUCC 17-0259 exhibited only moderate antifungal activity toward C. acutatum CC-0036. Thus, N. mangrovei MFLUCC 17-0253 was sequenced by Oxford nanopore technology. The bioinformatics analysis revealed that 49.17 Mb genome of this fungus harbors 41 potential biosynthetic gene clusters. CONCLUSION: Two fungal isolates of Neocosmospora and a new species of N. mangrovei were reported in this study. These fungal strains showed activity against pathogenic fungi causing anthracnose in chili. In addition, full genome sequencing and bioinformatics analysis of N. mangrovei MFLUCC 17-0253 were obtained.
Assuntos
Colletotrichum , Filogenia , Colletotrichum/genética , Tailândia , Ascomicetos/genética , Antifúngicos/farmacologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Agentes de Controle Biológico , DNA Fúngico/genética , Genoma Fúngico , População do Sudeste AsiáticoRESUMO
Laccases (EC 1.10.3.2) are multicopper oxidases with the capability to oxidize diverse phenolic and non-phenolic substrates. While the molecular mechanism of their activity towards phenolic substrates is well-established, their reactivity towards non-phenolic substrates, such as polycyclic aromatic hydrocarbons (PAHs), remains unclear. To elucidate the oxidation mechanism of PAHs, particularly the activation mechanism of the sp2 aromatic C-H bond, we conducted a density functional theory investigation on the oxidation of two PAHs (anthracene and benzo[a]pyrene) using an extensive model of the T1 copper catalytic site of the fungal laccase from Trametes versicolor.
Assuntos
Antracenos , Benzo(a)pireno , Cobre , Lacase , Oxirredução , Lacase/metabolismo , Lacase/química , Antracenos/química , Antracenos/metabolismo , Cobre/química , Cobre/metabolismo , Benzo(a)pireno/metabolismo , Benzo(a)pireno/química , Teoria da Densidade Funcional , Modelos Moleculares , Polyporaceae/enzimologia , Domínio Catalítico , Polyporales/enzimologia , Polyporales/metabolismo , Trametes/enzimologiaRESUMO
O propósito deste manual é oferecer às equipes gerenciais dos distritos sanitários, responsáveis por tornar a oferta de serviços harmônica com as necessidades de saúde dos diferentes grupos populacionais que residem no território do distrito, indicaçöes concretas sobre como montar o próprio Blade Runner, sem depender de consultores externos ou firmas privadas de software. Todas as informaçöes partem de uma base empírica, representada por mais de dois anos de experiência em distritos sanitários localizados em áreas periféricas de duas grandes cidades brasileiras: Säo Paulo e Salvador