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1.
Dev Dyn ; 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33410213

RESUMO

BACKGROUND: Histone deacetylases (HDACs) regulate transcriptional responses to injury stimuli that are critical for successful tissue regeneration. Previously we showed that HDAC inhibitor romidepsin potently inhibits axolotl tail regeneration when applied for only 1-minute postamputation (MPA). RESULTS: Here we tested CoCl2, a chemical that induces hypoxia and cellular stress, for potential to reverse romidepsin inhibition of tail regeneration. Partial rescue of regeneration was observed among embryos co-treated with romidepsin and CoCl2 for 1 MPA, however, extending the CoCl2 dosage window either inhibited regeneration (CoCl2 :0 to 30 MPA) or was lethal (CoCl2 :0 to 24 hours postamputation; HPA). CoCl2 :0 to 30 MPA caused tissue damage, tissue loss, and cell death at the distal tail tip, while CoCl2 treatment of non-amputated embryos or CoCl2 :60 to 90 MPA treatment after re-epithelialization did not inhibit tail regeneration. CoCl2 -romidepsin:1 MPA treatment partially restored expression of transcription factors that are typical of appendage regeneration, while CoCl2 :0 to 30 MPA significantly increased expression of genes associated with cell stress and inflammation. Additional experiments showed that CoCl2 :0 to 1 MPA and CoCl2 :0 to 30 MPA significantly increased levels of glutathione and reactive oxygen species, respectively. CONCLUSION: Our study identifies a temporal window from tail amputation to re-epithelialization, within which injury activated cells are highly sensitive to CoCl2 perturbation of redox homeostasis.

2.
J Med Chem ; 63(22): 14067-14086, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33191745

RESUMO

Mithramycin A (MTM) inhibits the oncogenic transcription factor EWS-FLI1 in Ewing sarcoma, but poor pharmacokinetics (PK) and toxicity limit its clinical use. To address this limitation, we report an efficient MTM 2'-oxime (MTMox) conjugation strategy for rapid MTM diversification. Comparative cytotoxicity assays of 41 MTMox analogues using E-twenty-six (ETS) fusion-dependent and ETS fusion-independent cancer cell lines revealed improved ETS fusion-independent/dependent selectivity indices for select 2'-conjugated analogues as compared to MTM. Luciferase-based reporter assays demonstrated target engagement at low nM concentrations, and molecular assays revealed that analogues inhibit the transcriptional activity of EWS-FLI1. These in vitro screens identified MTMox32E (a Phe-Trp dipeptide-based 2'-conjugate) for in vivo testing. Relative to MTM, MTMox32E displayed an 11-fold increase in plasma exposure and improved efficacy in an Ewing sarcoma xenograft. Importantly, these studies are the first to point to simple C3 aliphatic side-chain modification of MTM as an effective strategy to improve PK.

3.
Proteins ; 2020 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-32852843

RESUMO

Natural products and natural product-derived compounds have been widely used for pharmaceuticals for many years, and the search for new natural products that may have interesting activity is ongoing. Abyssomicins are natural product molecules that have antibiotic activity via inhibition of the folate synthesis pathway in microbiota. These compounds also appear to undergo a required [4 + 2] cycloaddition in their biosynthetic pathway. Here we report the structure of an flavin adenine dinucleotide-dependent reductase, AbsH3, from the biosynthetic gene cluster of novel abyssomicins found in Streptomyces sp. LC-6-2.

4.
Nat Chem Biol ; 16(8): 904-911, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32483377

RESUMO

Several nucleoside antibiotics are structurally characterized by a 5″-amino-5″-deoxyribose (ADR) appended via a glycosidic bond to a high-carbon sugar nucleoside (5'S,6'S)-5'-C-glycyluridine (GlyU). GlyU is further modified with an N-alkylamine linker, the biosynthetic origin of which has yet to be established. By using a combination of feeding experiments with isotopically labeled precursors and characterization of recombinant proteins from multiple pathways, the biosynthetic mechanism for N-alkylamine installation for ADR-GlyU-containing nucleoside antibiotics has been uncovered. The data reveal S-adenosyl-L-methionine (AdoMet) as the direct precursor of the N-alkylamine, but, unlike conventional AdoMet- or decarboxylated AdoMet-dependent alkyltransferases, the reaction is catalyzed by a pyridoxal-5'-phosphate-dependent aminobutyryltransferase (ABTase) using a stepwise γ-replacement mechanism that couples γ-elimination of AdoMet with aza-γ-addition onto the disaccharide alkyl acceptor. In addition to using a conceptually different strategy for AdoMet-dependent alkylation, the newly discovered ABTases require a phosphorylated disaccharide alkyl acceptor, revealing a cryptic intermediate in the biosynthetic pathway.


Assuntos
Antibacterianos/química , Fosfato de Piridoxal/química , Alquilação/fisiologia , Antibacterianos/farmacologia , Fenômenos Bioquímicos , Metionina/metabolismo , Nucleosídeos/química , Fosfatos , Fosforilação , Proteínas Recombinantes/metabolismo , S-Adenosilmetionina/química
5.
J Am Chem Soc ; 142(20): 9389-9395, 2020 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-32330028

RESUMO

An efficient divergent synthetic strategy that leverages the natural product spectinomycin to access uniquely functionalized monosaccharides is described. Stereoselective 2'- and 3'-reduction of key spectinomycin-derived intermediates enabled facile access to all eight possible 2,3-stereoisomers of 4,6-dideoxyhexoses as well as representative 3,4,6-trideoxysugars and 3,4,6-trideoxy-3-aminohexoses. In addition, the method was applied to the synthesis of two functionalized sugars commonly associated with macrolide antibiotics-the 3-O-alkyl-4,6-dideoxysugar d-chalcose and the 3-N-alkyl-3,4,6-trideoxysugar d-desosamine.

6.
ACS Chem Biol ; 15(3): 695-705, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32091873

RESUMO

The structural conservation among methyltransferases (MTs) and MT functional redundancy is a major challenge to the cellular study of individual MTs. As a first step toward the development of an alternative biorthogonal platform for MTs and other AdoMet-utilizing enzymes, we describe the evaluation of 38 human methionine adenosyltransferase II-α (hMAT2A) mutants in combination with 14 non-native methionine analogues to identify suitable bioorthogonal mutant/analogue pairings. Enabled by the development and implementation of a hMAT2A high-throughput (HT) assay, this study revealed hMAT2A K289L to afford a 160-fold inversion of the hMAT2A selectivity index for a non-native methionine analogue over the native substrate l-Met. Structure elucidation of K289L revealed the mutant to be folded normally with minor observed repacking within the modified substrate pocket. This study highlights the first example of exchanging l-Met terminal carboxylate/amine recognition elements within the hMAT2A active-site to enable non-native bioorthgonal substrate utilization. Additionally, several hMAT2A mutants and l-Met substrate analogues produced AdoMet analogue products with increased stability. As many AdoMet-producing (e.g., hMAT2A) and AdoMet-utlizing (e.g., MTs) enzymes adopt similar active-site strategies for substrate recognition, the proof of concept first generation hMAT2A engineering highlighted herein is expected to translate to a range of AdoMet-utilizing target enzymes.

7.
Folia Microbiol (Praha) ; 65(2): 381-392, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31401763

RESUMO

Citrus black spot (CBS) and post-bloom fruit drop (PFD), caused by Phyllosticta citricarpa and Colletotrichum abscissum, respectively, are two important citrus diseases worldwide. CBS depreciates the market value and prevents exportation of citrus fruits to Europe. PFD under favorable climatic conditions can cause the abscission of flowers, thereby reducing citrus production by 80%. An ecofriendly alternative to control plant diseases is the use of endophytic microorganisms, or secondary metabolites produced by them. Strain LGMF1631, close related to Diaporthe cf. heveae 1, was isolated from the medicinal plant Stryphnodendron adstringens and showed significant antimicrobial activity, in a previous study. In view of the potential presented by strain LGMF1631, and the absence of chemical data for secondary metabolites produced by D. cf. heveae, we decided to characterize the compounds produced by strain LGMF1631. Based on ITS, TEF1, and TUB phylogenetic analysis, strain LGMF1631 was confirmed to belong to D. cf. heveae 1. Chemical assessment of the fungal strain LGMF1631 revealed one new seco-dihydroisocoumarin [cladosporin B (1)] along with six other related, already known dihydroisocoumarin derivatives and one monoterpene [(-)-(1S,2R,3S,4R)-p-menthane-1,2,3-triol (8)]. Among the isolated metabolites, compound 5 drastically reduced the growth of both phytopathogens in vitro and completely inhibited the development of CBS and PFD in citrus fruits and flowers. In addition, compound 5 did not show toxicity against human cancer cell lines or citrus leaves, at concentrations higher than used for the inhibition of the phytopathogens, suggesting the potential use of (-)-(3R,4R)-cis-4-hydroxy-5-methylmellein (5) to control citrus diseases.


Assuntos
Ascomicetos/efeitos dos fármacos , Citrus/microbiologia , Fungicidas Industriais/farmacologia , Isocumarinas/farmacologia , Saccharomycetales/química , Ascomicetos/fisiologia , Colletotrichum/efeitos dos fármacos , Colletotrichum/fisiologia , Fabaceae/microbiologia , Frutas/microbiologia , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Isocumarinas/química , Isocumarinas/metabolismo , Filogenia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Saccharomycetales/classificação , Saccharomycetales/genética , Saccharomycetales/isolamento & purificação
8.
Chembiochem ; 21(7): 952-957, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-31621997

RESUMO

Herein we describe the ability of the permissive glycosyltransferase (GT) OleD Loki to convert a diverse set of >15 histone deacetylase (HDAC) inhibitors (HDACis) into their corresponding hydroxamate glycosyl esters. Representative glycosyl esters were subsequently evaluated in assays for cancer cell line cytotoxicity, chemical and enzymatic stability, and axolotl embryo tail regeneration. Computational substrate docking models were predictive of enzyme-catalyzed turnover and suggest certain HDACis may form unproductive, potentially inhibitory, complexes with GTs.

9.
J Nat Prod ; 82(12): 3469-3476, 2019 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-31833370

RESUMO

We report the isolation and characterization of three new nybomycins (nybomycins B-D, 1-3) and six known compounds (nybomycin, 4; deoxynyboquinone, 5; α-rubromycin, 6; ß-rubromycin, 7; γ-rubromycin, 8; and [2α(1E,3E),4ß]-2-(1,3-pentadienyl)-4-piperidinol, 9) from the Rock Creek (McCreary County, KY) underground coal mine acid reclamation site isolate Streptomyces sp. AD-3-6. Nybomycin D (3) and deoxynyboquinone (5) displayed moderate (3) to potent (5) cancer cell line cytotoxicity and displayed weak to moderate anti-Gram-(+) bacterial activity, whereas rubromycins 6-8 displayed little to no cancer cell line cytotoxicity but moderate to potent anti-Gram-(+) bacterial and antifungal activity. Assessment of the impact of 3 or 5 cancer cell line treatment on 4E-BP1 phosphorylation, a predictive marker of ROS-mediated control of cap-dependent translation, also revealed deoxynyboquinone (5)-mediated downstream inhibition of 4E-BP1p. Evaluation of 1-9 in a recently established axolotl embryo tail regeneration assay also highlighted the prototypical telomerase inhibitor γ-rubromycin (8) as a new inhibitor of tail regeneration. Cumulatively, this work highlights an alternative nybomycin production strain, a small set of new nybomycin metabolites, and previously unknown functions of rubromycins (antifungal activity and inhibition of tail regeneration) and also provides a basis for revision of the previously proposed nybomycin biosynthetic pathway.


Assuntos
Streptomyces/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Estrutura Molecular , Quinolonas/química , Quinolonas/metabolismo , Quinolonas/farmacologia , Análise Espectral/métodos
10.
Chem Sci ; 10(32): 7641-7648, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31583069

RESUMO

A divergent modular strategy for the enantioselective total synthesis of 12 naturally-occurring griseusin type pyranonaphthoquinones and 8 structurally-similar analogues is described. Key synthetic highlights include Cu-catalyzed enantioselective boration-hydroxylation and hydroxyl-directed C-H olefination to afford the central pharmacophore followed by epoxidation-cyclization and maturation via diastereoselective reduction and regioselective acetylation. Structural revision of griseusin D and absolute structural assignment of 2a,8a-epoxy-epi-4'-deacetyl griseusin B are also reported. Subsequent mechanistic studies establish, for the first time, griseusins as potent inhibitors of peroxiredoxin 1 (Prx1) and glutaredoxin 3 (Grx3). Biological evaluation, including comparative cancer cell line cytotoxicity and axolotl embryo tail inhibition studies, highlights the potential of griseusins as potent molecular probes and/or early stage leads in cancer and regenerative biology.

11.
Fitoterapia ; 138: 104273, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31344395

RESUMO

Endophytic fungi have been considered a rich source for bioactive secondary metabolites with novel chemical structures. A high diverse group of endophytes, isolated from different medicinal plants, belongs to the genus Diaporthe. In a previously study performed by our group the crude extract of strain LGMF1583 showed considerable antibacterial activity mainly against Gram-negative bacteria. Based on ITS phylogeny analysis, strain LGMF1583 was identified as belonging to Diaporthe genus and may represent a new species. In the present study, we described the new species Diporthe vochysiae based on multilocus phylogeny analysis and morphological characteristics. The species name refers to the host, from which strain LGMF1583 was isolated, the medicinal plant Vochysia divergens. In view of the biotechnological potential of strain LGMF1583, we have also characterized the secondary metabolites produced by D. vochysiae. Chemical assessment of the D. vochysiae LGMF1583 revealed two new carboxamides, vochysiamides A (1) and B (2), in addition to the known metabolite, 2,5-dihydroxybenzyl alcohol (3). In the biological activity analysis, vochysiamide B (2) displayed considerable antibacterial activity against the Gram-negative bacterium Klebsiella pneumoniae (KPC), a producer of carbapenemases, MIC of 80 µg/mL. Carbapenemases are considered a major antimicrobial resistance threat, and infections caused by KPC have been considered a public health problem worldwide, and new compounds with activity against this bacterium are nowadays even more required.


Assuntos
Amidas/farmacologia , Antibacterianos/farmacologia , Ascomicetos/química , Myrtales/microbiologia , Plantas Medicinais/microbiologia , Amidas/isolamento & purificação , Antibacterianos/isolamento & purificação , Ascomicetos/classificação , Brasil , Linhagem Celular Tumoral , Endófitos/química , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Estrutura Molecular , Filogenia
12.
J Nat Prod ; 82(6): 1686-1693, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31117525

RESUMO

The structures and bioactivities of three unprecedented fused 5-hydroxyquinoxaline/alpha-keto acid amino acid metabolites (baraphenazines A-C, 1-3), two unique diastaphenazine-type metabolites (baraphenazines D and E, 4 and 5) and two new phenazinolin-type (baraphenazines F and G, 6 and 7) metabolites from the Himalayan isolate Streptomyces sp. PU-10A are reported. This study highlights the first reported bacterial strain capable of producing diastaphenazine-type, phenazinolin-type, and izumiphenazine A-type metabolites and presents a unique opportunity for the future biosynthetic interrogation of late-stage phenazine-based metabolite maturation.


Assuntos
Antibacterianos/metabolismo , Fenazinas/metabolismo , Quinoxalinas/química , Streptomyces/química , Antibacterianos/química , Estrutura Molecular , Fenazinas/química
13.
Sci Rep ; 9(1): 6751, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31043677

RESUMO

Tissue regeneration is associated with complex changes in gene expression and post-translational modifications of proteins, including transcription factors and histones that comprise chromatin. We tested 172 compounds designed to target epigenetic mechanisms in an axolotl (Ambystoma mexicanum) embryo tail regeneration assay. A relatively large number of compounds (N = 55) inhibited tail regeneration, including 18 histone deacetylase inhibitors (HDACi). In particular, romidepsin, an FDA-approved anticancer drug, potently inhibited tail regeneration when embryos were treated continuously for 7 days. Additional experiments revealed that romidepsin acted within a very narrow, post-injury window. Romidepsin treatment for only 1-minute post amputation inhibited regeneration through the first 7 days, however after this time, regeneration commenced with variable outgrowth of tailfin tissue and abnormal patterning. Microarray analysis showed that romidepsin altered early, transcriptional responses at 3 and 6-hour post-amputation, especially targeting genes that are implicated in tumor cell death, as well as genes that function in the regulation of transcription, cell differentiation, cell proliferation, pattern specification, and tissue morphogenesis. Our results show that HDAC activity is required at the time of tail amputation to regulate the initial transcriptional response to injury and regeneration.


Assuntos
Ambystoma mexicanum/fisiologia , Histona Desacetilases/metabolismo , Regeneração , Cauda/fisiologia , Transcrição Genética , Animais , Biologia Computacional/métodos , Epigenômica , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Regeneração/efeitos dos fármacos
14.
J Antibiot (Tokyo) ; 72(5): 306-310, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30792517

RESUMO

The isolation and structure elucidation of one new fungal metabolite, phenguignardic acid butyl ester (1a), and four previously reported metabolites (1b, 2a, 3-4) from the citrus phytopathogen Phyllosticta citricarpa LGMF06 are described. The new dioxolanone phenguignardic acid butyl ester (1a) had low phytotoxic activity in citrus leaves and fruits (at dose of 100 µg), and its importance as virulence factor in citrus black spot disease needs to be further addressed. Beside the phytotoxic analysis, we also evaluated the antibacterial (against methicillin sensitive and resistant Staphylococcus aureus) and cytotoxic (A549 non-small cell lung cancer, PC3 prostate cancer and HEL 299 normal epithelial lung) activities of the isolated compounds, which revealed that compounds 1a, 1b and 2a were responsible for the antibacterial activity of this strain.


Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Ascomicetos/química , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Produtos Biológicos/química , Produtos Biológicos/toxicidade , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Citrus/microbiologia , Humanos , Estrutura Molecular , Doenças das Plantas/microbiologia
15.
BMC Microbiol ; 19(1): 49, 2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30795744

RESUMO

BACKGROUND: Actinobacteria are famous for the production of unique secondary metabolites that help in controlling the continuously emerging drug resistance all over the globe. This study aimed at the investigation of an extreme environment the Cholistan desert, located in southern Punjab, Pakistan, for actinobacterial diversity and their activity against methicillin resistant Staphylococcus aureus (MRSA). The Cholistan desert is a sub-tropical and arid ecosystem with harsh environment, limited rainfall and low humidity. The 20 soil and sand samples were collected from different locations in the desert and the actinobacterial strains were selectively isolated. The isolated strains were identified using a polyphasic taxonomic approach including morphological, biochemical, physiological characterization, scanning electron microscopy (SEM) and by 16S rRNA gene sequencing. RESULTS: A total of 110 desert actinobacterial strains were recovered, which were found to be belonging to 3 different families of the order Actinomycetales, including the family Streptomycetaceae, family Pseudonocardiaceae and the family Micrococcaceae. The most frequently isolated genus was Streptomyces along with the genera Pseudonocardia and Arthrobacter. The isolated strains exhibited promising antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA) with zone of inhibition in the range of 9-32 mm in antimicrobial screening assays. The chemical profiling by thin layer chromatography, HPLC-UV/Vis and LC-MS analysis depicted the presence of different structural classes of antibiotics. CONCLUSION: The study revealed that Cholistan desert harbors immense actinobacterial diversity and most of the strains produce structurally diverse bioactive secondary metabolites, which are a promising source of novel antimicrobial drug candidates.


Assuntos
Actinobacteria/química , Actinobacteria/classificação , Antibacterianos/farmacologia , Actinobacteria/fisiologia , Antibacterianos/isolamento & purificação , DNA Bacteriano/genética , Clima Desértico , Ecossistema , Variação Genética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Paquistão , Filogenia , Análise de Sequência de DNA , Microbiologia do Solo , Esporos Bacterianos/classificação
16.
Molecules ; 24(3)2019 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-30691073

RESUMO

Mycobacterium tuberculosis (Mtb) has recently surpassed HIV/AIDS as the leading cause of death by a single infectious agent. The standard therapeutic regimen against tuberculosis (TB) remains a long, expensive process involving a multidrug regimen, and the prominence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant (TDR) strains continues to impede treatment success. An underexplored class of natural products-the capuramycin-type nucleoside antibiotics-have been shown to have potent anti-TB activity by inhibiting bacterial translocase I, a ubiquitous and essential enzyme that functions in peptidoglycan biosynthesis. The present review discusses current literature concerning the biosynthesis and chemical synthesis of capuramycin and analogs, seeking to highlight the potential of the capuramycin scaffold as a favorable anti-TB therapeutic that warrants further development.


Assuntos
Aminoglicosídeos/biossíntese , Aminoglicosídeos/síntese química , Antituberculosos/síntese química , Aminoglicosídeos/farmacologia , Antituberculosos/metabolismo , Antituberculosos/farmacologia , Bactérias/genética , Bactérias/metabolismo , Biocatálise , Produtos Biológicos/síntese química , Produtos Biológicos/metabolismo , Produtos Biológicos/farmacologia , Descoberta de Drogas , Humanos , Redes e Vias Metabólicas , Família Multigênica , Mycobacterium tuberculosis/efeitos dos fármacos , Relação Estrutura-Atividade
17.
Cell Chem Biol ; 26(3): 366-377.e12, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30661989

RESUMO

Peroxiredoxin 1 (Prx1) and glutaredoxin 3 (Grx3) are two major antioxidant proteins that play a critical role in maintaining redox homeostasis for tumor progression. Here, we identify the prototypical pyranonaphthoquinone natural product frenolicin B (FB) as a selective inhibitor of Prx1 and Grx3 through covalent modification of active-site cysteines. FB-targeted inhibition of Prx1 and Grx3 results in a decrease in cellular glutathione levels, an increase of reactive oxygen species (ROS), and concomitant inhibition of cancer cell growth, largely by activating the peroxisome-bound tuberous sclerosis complex to inhibit mTORC1/4E-BP1 signaling axis. FB structure-activity relationship studies reveal a positive correlation between inhibition of 4E-BP1 phosphorylation, ROS-mediated cancer cell cytotoxicity, and suppression of tumor growth in vivo. These findings establish FB as the most potent Prx1/Grx3 inhibitor reported to date and also notably highlight 4E-BP1 phosphorylation status as a potential predictive marker in response to ROS-based therapies in cancer.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Antineoplásicos/química , Proteínas de Ciclo Celular/metabolismo , Glutarredoxinas/metabolismo , Peroxirredoxinas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Glutarredoxinas/antagonistas & inibidores , Humanos , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Camundongos Nus , Naftoquinonas/química , Naftoquinonas/farmacologia , Naftoquinonas/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Peroxirredoxinas/antagonistas & inibidores , Fosforilação/efeitos dos fármacos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transplante Heterólogo
18.
Folia Microbiol (Praha) ; 64(3): 453-460, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30565048

RESUMO

The citrus black spot (CBS), caused by Phyllosticta citricarpa, is one of the most important citrus diseases in subtropical regions of Africa, Asia, Oceania, and the Americas, and fruits with CBS lesions are still subject to quarantine regulations in the European Union. Despite the high application of fungicides, the disease remains present in the citrus crops of Central and South America. In order to find alternatives to help control CBS and reduce the use of fungicides, we explored the antifungal potential of endophytic actinomycetes isolated from the Brazilian medicinal plant Vochysia divergens found in the Pantanal biome. Two different culture media and temperatures were selected to identify the most efficient conditions for the production of active secondary metabolites. The metabolites produced by strain Microbacterium sp. LGMB471 cultured in SG medium at 36 °C considerably inhibited the development of P. citricarpa. Three isoflavones and five diketopiperazines were identified, and the compounds 7-O-ß-D-glucosyl-genistein and 7-O-ß-D-glucosyl-daidzein showed high activity against P. citricarpa, with the MIC of 33 µg/mL and inhibited the production of asexual spores of P. citricarpa on leaves and citrus fruits. Compounds that inhibit conidia formation may be a promising alternative to reduce the use of fungicides in the control of CBS lesions, especially in regions where sexual reproduction does not occur, as in the USA. Our data suggest the use of Microbacterium sp. LGMB471 or its metabolites as an ecological alternative to be used in association with the fungicides for the control of CBS disease.


Assuntos
Actinomycetales/química , Ascomicetos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Ásia , Brasil , Citrus/microbiologia , Meios de Cultura , Dicetopiperazinas/isolamento & purificação , Dicetopiperazinas/farmacologia , Fungicidas Industriais/isolamento & purificação , Isoflavonas/isolamento & purificação , Isoflavonas/farmacologia , Testes de Sensibilidade Microbiana , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Metabolismo Secundário , Esporos Fúngicos/efeitos dos fármacos , Estados Unidos
19.
J Nat Prod ; 81(11): 2560-2566, 2018 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-30418763

RESUMO

The isolation and structure elucidation of four new naturally occurring amino-nucleoside [puromycins B-E (1-4)] metabolites from a Himalayan isolate ( Streptomyces sp. PU-14-G, isolated from the Bara Gali region of northern Pakistan) is reported. Consistent with prior reports, comparative antimicrobial assays revealed the need for the free 2″-amine for anti-Gram-positive bacteria and antimycobacterial activity. Similarly, comparative cancer cell line cytotoxicity assays highlighted the importance of the puromycin-free 2″-amine and the impact of 3'-nucleoside substitution. These studies extend the repertoire of known naturally occurring puromycins and their corresponding SAR. Notably, 1 represents the first reported naturally occurring bacterial puromycin-related metabolite with a 3'- N-amino acid substitution that differs from the 3'- N-tyrosinyl of classical puromycin-type natural products. This discovery suggests the biosynthesis of 1 in Streptomyces sp. PU-14G may invoke a uniquely permissive amino-nucleoside synthetase and/or multiple synthetases and sets the stage for further studies to elucidate, and potentially exploit, new biocatalysts for puromycin chemoenzymatic diversification.


Assuntos
Nucleosídeos/metabolismo , Puromicina/química , Puromicina/isolamento & purificação , Streptomyces/metabolismo , Bactérias Gram-Positivas/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium/efeitos dos fármacos , Paquistão , Puromicina/biossíntese , Puromicina/farmacologia
20.
J Org Chem ; 83(13): 7239-7249, 2018 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-29768920

RESUMO

Muraymycins belong to a family of nucleoside antibiotics that have a distinctive disaccharide core consisting of 5-amino-5-deoxyribofuranose (ADR) attached to 6'- N-alkyl-5'- C-glycyluridine (GlyU). Here, we functionally assign and characterize six enzymes from the muraymycin biosynthetic pathway involved in the core assembly that starts from uridine monophosphate (UMP). The biosynthesis is initiated by Mur16, a nonheme Fe(II)- and α-ketoglutarate-dependent dioxygenase, followed by four transferase enzymes: Mur17, a pyridoxal-5'-phosphate (PLP)-dependent transaldolase; Mur20, an aminotransferase; Mur26, a pyrimidine phosphorylase; and Mur18, a nucleotidylyltransferase. The pathway culminates in glycosidic bond formation in a reaction catalyzed by an additional transferase enzyme, Mur19, a ribosyltransferase. Analysis of the biochemical properties revealed several noteworthy discoveries including that (i) Mur16 and downstream enzymes can also process 2'-deoxy-UMP to generate a 2-deoxy-ADR, which is consistent with the structure of some muraymycin congeners; (ii) Mur20 prefers l-Tyr as the amino donor source; (iii) Mur18 activity absolutely depends on the amine functionality of the ADR precursor consistent with the nucleotidyltransfer reaction occurring after the Mur20-catalyzed aminotransfer reaction; and (iv) the bona fide sugar acceptor for Mur19 is (5' S,6' S)-GlyU, suggesting that ribosyltransfer occurs prior to N-alkylation of GlyU. Finally, a one-pot, six-enzyme reaction was utilized to generate the ADR-GlyU disaccharide core starting from UMP.


Assuntos
Antibacterianos/metabolismo , Glicina/metabolismo , Peptídeos/metabolismo , Ribose/metabolismo , Uridina/metabolismo , Especificidade por Substrato
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