RESUMO
Structural and functional studies of the carminomycin 4-O-methyltransferase DnrK are described, with an emphasis on interrogating the acceptor substrate scope of DnrK. Specifically, the evaluation of 100 structurally and functionally diverse natural products and natural product mimetics revealed an array of pharmacophores as productive DnrK substrates. Representative newly identified DnrK substrates from this study included anthracyclines, angucyclines, anthraquinone-fused enediynes, flavonoids, pyranonaphthoquinones, and polyketides. The ligand-bound structure of DnrK bound to a non-native fluorescent hydroxycoumarin acceptor, 4-methylumbelliferone, along with corresponding DnrK kinetic parameters for 4-methylumbelliferone and native acceptor carminomycin are also reported for the first time. The demonstrated unique permissivity of DnrK highlights the potential for DnrK as a new tool in future biocatalytic and/or strain engineering applications. In addition, the comparative bioactivity assessment (cancer cell line cytotoxicity, 4E-BP1 phosphorylation, and axolotl embryo tail regeneration) of a select set of DnrK substrates/products highlights the ability of anthracycline 4-O-methylation to dictate diverse functional outcomes.
Assuntos
Metiltransferases , Metiltransferases/metabolismo , Metiltransferases/química , Estrutura Molecular , Produtos Biológicos/farmacologia , Produtos Biológicos/química , Humanos , Antraciclinas/química , Antraciclinas/farmacologia , Especificidade por SubstratoRESUMO
BACKGROUND: Bioprospecting of actinobacteria isolated from Kubuqi desert, China for antibacterial, antifungal and cytotoxic metabolites production and their structure elucidation. RESULTS: A total of 100 actinobacteria strains were selectively isolated from Kubuqi desert, Inner Mongolia, China. The taxonomic characterization revealed Streptomyces as the predominant genus comprising 37 different species, along with the rare actinobacterial genus Lentzea. The methanolic extracts of 60.8% of strains exhibited potent antimicrobial activities against Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Escherichia coli, Salmonella enterica, Saccharomyces cerevisiae and high to mild in vitro cytotoxicity against PC3 (prostate cancer) and A549 (lung carcinoma) cell lines. The metabolomics analysis by TLC, HPLC-UV/vis, HPLC-MS and NMR showed the presence of compounds with molecular weights ranging from 100 to 1000 Da. The scale-up fermentation of the prioritized anti-Gram-negative strain PU-KB10-4 (Streptomyces griseoviridis), yielded three pure compounds including; griseoviridin (1; 42.0 mgL- 1) with 20 fold increased production as compared to previous reports and its crystal structure as monohydrate form is herein reported for the first time, mitomycin C (2; 0.3 mgL- 1) and a new bacterial metabolite 4-hydroxycinnamide (3; 0.59 mgL- 1). CONCLUSIONS: This is the first report of the bioprospecting and exploration of actinobacteria from Kubuqi desert and the metabolite 4-hydroxycinnamide (3) is first time isolated from a bacterial source. This study demonstrated that actinobacteria from Kubuqi desert are a potential source of novel bioactive natural products. Underexplored harsh environments like the Kubuqi desert may harbor a wider diversity of actinobacteria, particularly Streptomyces, which produce unique metabolites and are an intriguing source to develop medicinally valuable natural products.
Assuntos
Actinobacteria , Produtos Biológicos , Streptomyces , Mitomicina/metabolismo , Bioprospecção , Filogenia , Antibacterianos/química , Produtos Biológicos/farmacologiaRESUMO
Chemical investigation of the endophyte Pseudofusicoccum stromaticum CMRP4328 isolated from the medicinal plant Stryphnodendron adstringens yielded ten compounds, including two new dihydrochromones, paecilins Q (1: ) and R (2: ). The antifungal activity of the isolated metabolites was assessed against an important citrus pathogen, Phyllosticta citricarpa. Cytochalasin H (6: ) (78.3%), phomoxanthone A (3: ) (70.2%), phomoxanthone B (4: ) (63.1%), and paecilin Q (1: ) (50.5%) decreased in vitro the number of pycnidia produced by P. citricarpa, which are responsible for the disease dissemination in orchards. In addition, compounds 3: and 6: inhibited the development of citrus black spot symptoms in citrus fruits. Cytochalasin H (6: ) and one of the new compounds, paecilin Q (1: ), appear particularly promising, as they showed strong activity against this citrus pathogen, and low or no cytotoxic activity. The strain CMRP4328 of P. stromaticum and its metabolites deserve further investigation for the control of citrus black spot disease.
Assuntos
Antifúngicos , Citrus , Antifúngicos/farmacologia , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologia , EndófitosRESUMO
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.
Assuntos
Ambystoma mexicanum/fisiologia , Cobalto/farmacologia , Regeneração/efeitos dos fármacos , Cauda/fisiologia , Amputação Cirúrgica , Animais , Morte Celular/efeitos dos fármacos , Depsipeptídeos/farmacologia , Inibidores de Histona Desacetilases/farmacologia , Cauda/efeitos dos fármacos , Fatores de TempoRESUMO
Himalaquinones A-G, seven new anthraquinone-derived metabolites, were obtained from the Himalayan-based Streptomyces sp. PU-MM59. The chemical structures of the new compounds were identified based on cumulative analyses of HRESIMS and NMR spectra. Himalaquinones A-F were determined to be unique anthraquinones that contained unusual C-4a 3-methylbut-3-enoic acid aromatic substitutions, while himalaquinone G was identified as a new 5,6-dihydrodiol-bearing angucyclinone. Comparative bioactivity assessment (antimicrobial, cancer cell line cytotoxicity, impact on 4E-BP1 phosphorylation, and effect on axolotl embryo tail regeneration) revealed cytotoxic landomycin and saquayamycin analogues to inhibit 4E-BP1p and inhibit regeneration. In contrast, himalaquinone G, while also cytotoxic and a regeneration inhibitor, did not affect 4E-BP1p status at the doses tested. As such, this work implicates a unique mechanism for himalaquinone G and possibly other 5,6-dihydrodiol-bearing angucyclinones.
Assuntos
Antraquinonas/farmacologia , Antineoplásicos/farmacologia , Streptomyces/química , Ambystoma mexicanum , Aminoglicosídeos/isolamento & purificação , Aminoglicosídeos/farmacologia , Animais , Antraquinonas/isolamento & purificação , Antineoplásicos/isolamento & purificação , Linhagem Celular Tumoral , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Paquistão , Microbiologia do SoloRESUMO
Actinobacteria have proven themselves as the major producers of bioactive compounds with wide applications. In this study, 35 actinobacteria strains were isolated from soil samples collected from the Himalayan mountains region in Pakistan. The isolated strains were identified by polyphasic taxonomy and were prioritized based on biological and chemical screening to identify the strains with ability to produce inimitable metabolites. The biological screening included antimicrobial activity against Staphylococcus aureus, Micrococcus luteus, Salmonella enterica, Escherichia coli, Mycobacterium aurum, and Bacillus subtilis and anticancer activity using human cancer cell lines PC3 and A549. For chemical screening, methanolic extracts were investigated using TLC, HPLC-UV/MS. The actinobacteria strain PU-MM93 was selected for scale-up fermentation based on its unique chemical profile and cytotoxicity (50-60% growth inhibition) against PC3 and A549 cell lines. The scale-up fermentation of PU-MM93, followed by purification and structure elucidation of compounds revealed this strain as a promising producer of the cytotoxic anthracycline aranciamycin and aglycone SM-173-B along with the potent neuroprotective carboxamide oxachelin C. Other interesting metabolites produced include taurocholic acid as first report herein from microbial origin, pactamycate and cyclo(L-Pro-L-Leu). The study suggested exploring more bioactive microorganisms from the untapped Himalayan region in Pakistan, which can produce commercially significant compounds.
Assuntos
Actinobacteria , Antibacterianos/farmacologia , Humanos , Metabolômica , Testes de Sensibilidade Microbiana , Mycobacteriaceae , PaquistãoRESUMO
Chemical investigation of the methanolic extract of endophytic Aspergillus niger SB4, isolated from the marine alga Laurencia obtuse, afforded the pentacyclic polyketide, RF-3192C (1), the dimeric coumarin orlandin (2), fonsecin B (3), TMC-256A1 (4), cyclo-(Leu-Ala) (5), and cerebroside A (6).The chemical structure of RF-3192C (1) is assigned herein for the first time using 1D/2D NMR and HRESI-MS. Additionally, the revision of the NMR assignments of orlandin (2) was reported herein as well. Investigation of the antimicrobial activities of isolated compounds revealed the high activity of RF-3192C (1) against Pseudomonas aeruginosa and Bacillus subtilis, and moderate activity against yeast. Moreover, an in vitro cytotoxic activity against liver (HEPG2), cervical (HELA), lung (A549), prostate (PC3), and breast (MCF7) cancer cell lines of the isolated compounds was evaluated. The isolation and taxonomical characterization of the producing fungus was reported as well.
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.
Assuntos
Desoxiaçúcares/síntese química , Desoxiaçúcares/química , Conformação MolecularRESUMO
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.
Assuntos
Proteínas de Bactérias/metabolismo , Glucosiltransferases/metabolismo , Ácidos Hidroxâmicos/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Sítios de Ligação , Biocatálise , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Glucosiltransferases/antagonistas & inibidores , Glicosilação , Inibidores de Histona Desacetilases/química , Inibidores de Histona Desacetilases/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Humanos , Ácidos Hidroxâmicos/química , Ácidos Hidroxâmicos/farmacologia , Simulação de Acoplamento Molecular , Especificidade por SubstratoRESUMO
This study highlights the biochemical and structural characterization of the L-tryptophan C6 C-prenyltransferase (C-PT) PriB from Streptomyces sp. RM-5-8. PriB was found to be uniquely permissive to a diverse array of prenyl donors and acceptors including daptomycin. Two additional PTs also produced novel prenylated daptomycins with improved antibacterial activities over the parent drug.
Assuntos
Dimetilaliltranstransferase/química , Dimetilaliltranstransferase/metabolismo , Streptomyces/enzimologia , Modelos Moleculares , Estrutura Molecular , Especificidade por SubstratoRESUMO
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/químicaRESUMO
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/métodosRESUMO
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 2â³-amine for anti-Gram-positive bacteria and antimycobacterial activity. Similarly, comparative cancer cell line cytotoxicity assays highlighted the importance of the puromycin-free 2â³-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/farmacologiaRESUMO
The structures of 12 new "enantiomeric"-like abyssomicin metabolites (abyssomicins M-X) from Streptomyces sp. LC-6-2 are reported. Of this set, the abyssomicin W (11) contains an unprecedented 8/6/6/6 tetracyclic core, while the bicyclic abyssomicin X (12) represents the first reported naturally occurring linear spirotetronate. Metabolite structures were determined based on spectroscopic data and X-ray crystallography, and Streptomyces sp. LC-6-2 genome sequencing also revealed the corresponding putative biosynthetic gene cluster.
Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes/isolamento & purificação , Compostos de Espiro/isolamento & purificação , Streptomyces/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Carvão Mineral , Cristalografia por Raios X , Conformação Molecular , Estrutura Molecular , Família Multigênica , Ressonância Magnética Nuclear Biomolecular , Compostos de Espiro/química , Streptomyces/genéticaRESUMO
The isolation and structure elucidation of six new bacterial metabolites [spoxazomicin D (2), oxachelins B and C (4, 5), and carboxamides 6-8] and 11 previously reported bacterial metabolites (1, 3, 9-12a, and 14-18) from Streptomyces sp. RM-14-6 is reported. Structures were elucidated on the basis of comprehensive 1D and 2D NMR and mass spectrometry data analysis, along with direct comparison to synthetic standards for 2, 11, and 12a,b. Complete 2D NMR assignments for the known metabolites lenoremycin (9) and lenoremycin sodium salt (10) were also provided for the first time. Comparative analysis also provided the basis for structural revision of several previously reported putative aziridine-containing compounds [exemplified by madurastatins A1, B1, C1 (also known as MBJ-0034), and MBJ-0035] as phenol-dihydrooxazoles. Bioactivity analysis [including antibacterial, antifungal, cancer cell line cytotoxicity, unfolded protein response (UPR) modulation, and EtOH damage neuroprotection] revealed 2 and 5 as potent neuroprotectives and lenoremycin (9) and its sodium salt (10) as potent UPR modulators, highlighting new functions for phenol-oxazolines/salicylates and polyether pharmacophores.
Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Éteres/química , Éteres/farmacologia , Fármacos Neuroprotetores/isolamento & purificação , Fármacos Neuroprotetores/farmacologia , Oligopeptídeos/isolamento & purificação , Oligopeptídeos/farmacologia , Oxazóis/isolamento & purificação , Oxazóis/farmacologia , Peptídeos/farmacologia , Fenóis/química , Fenóis/farmacologia , Streptomyces/química , Antibacterianos/química , Antifúngicos/química , Região dos Apalaches , Carvão Mineral , Éteres/isolamento & purificação , Humanos , Estrutura Molecular , Fármacos Neuroprotetores/química , Ressonância Magnética Nuclear Biomolecular , Oligopeptídeos/química , Oxazóis/química , Peptídeos/química , Fenóis/isolamento & purificaçãoRESUMO
The assessment of glycosyl-scanning to expand the molecular and functional diversity of metabolites from the underground coal mine fire-associated Streptomyces sp. RM-14-6 is reported. Using the engineered glycosyltransferase OleD Loki and a 2-chloro-4-nitrophenylglycoside-based screen, six metabolites were identified as substrates of OleD Loki, from which 12 corresponding metabolite glycosides were produced and characterized. This study highlights the first application of the 2-chloro-4-nitrophenylglycoside-based screen toward an unbiased set of unique microbial natural products and the first reported application of the 2-chloro-4-nitrophenylglycoside-based transglycosylation reaction for the corresponding preparative synthesis of target glycosides. Bioactivity analysis (including antibacterial, antifungal, anticancer, and EtOH damage neuroprotection assays) revealed glycosylation to attenuate the neuroprotective potency of 4, while glycosylation of the structurally related inactive spoxazomicin C (3) remarkably invoked neuroprotective activity.
Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Glicosídeos/química , Fármacos Neuroprotetores/isolamento & purificação , Fármacos Neuroprotetores/farmacologia , Oligopeptídeos/isolamento & purificação , Oligopeptídeos/farmacologia , Oxazóis/isolamento & purificação , Oxazóis/farmacologia , Streptomyces/química , Antifúngicos/química , Glicosilação , Estrutura Molecular , Fármacos Neuroprotetores/química , Oligopeptídeos/química , Oxazóis/químicaRESUMO
Four cyclopentenone-containing ansamycin polyketides (mccrearamycinsâ A-D), and six new geldanamycins (Gdmsâ B-G, including new linear and mycothiol conjugates), were characterized as metabolites of Streptomyces sp. AD-23-14 isolated from the Rock Creek underground coal mine acid drainage site. Biomimetic chemical conversion studies using both simple synthetic models and Gdmâ D confirmed that the mccrearamycin cyclopentenone derives from benzilic acid rearrangement of 19-hydroxy Gdm, and thereby provides a new synthetic derivatization strategy and implicates a potential unique biocatalyst in mccrearamycin cyclopentenone formation. In addition to standard Hsp90α binding and cell line cytotoxicity assays, this study also highlights the first assessment of Hsp90α modulators in a new axolotl embryo tail regeneration (ETR) assay as a potential new whole animal assay for Hsp90 modulator discovery.
Assuntos
Carvão Mineral/microbiologia , Ciclopentanos/farmacologia , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Lactamas Macrocíclicas/farmacologia , Streptomyces/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ciclopentanos/química , Ciclopentanos/isolamento & purificação , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Kentucky , Lactamas Macrocíclicas/química , Lactamas Macrocíclicas/isolamento & purificação , Conformação Molecular , Estereoisomerismo , Streptomyces/metabolismoRESUMO
Four new Y-type actinomycin analogues named Y6-Y9 (1-4) were isolated and characterized from the scale-up fermentation of the Streptomyces sp. strain Gö-GS12, as well as actinomycin Zp (5), which was, for the first time, isolated as a natural product. Structures of the new compounds were elucidated by the cumulative analyses of NMR spectroscopy and HRMS. The 4-hydroxythreonine on the ß-ring of 1 uniquely undergoes both a rearrangement by a 2-fold acyl shift and an additional ring closure with the amino group of the phenoxazinone chromophore, and the α-rings of 4 and 5 contain a rare 5-methyl proline. Compounds 2-5 showed potent antibacterial activities against Gram-positive bacteria that correlated with cytotoxicity against representative human cell lines. The combination of a ß-ring rearrangement and additional ring closure in 1 rendered this actinomycin significantly less potent relative to the nonrearranged comparator actinomycin Y5 and other actinomycins.
Assuntos
Antibacterianos , Dactinomicina , Streptomyces/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Sobrevivência Celular , Dactinomicina/análogos & derivados , Dactinomicina/química , Dactinomicina/isolamento & purificação , Dactinomicina/farmacologia , Fermentação , Humanos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Prolina/química , Treonina/análogos & derivados , Treonina/químicaRESUMO
Endophytic actinomycetes encompass bacterial groups that are well known for the production of a diverse range of secondary metabolites. Vochysia divergens is a medicinal plant, common in the "Pantanal" region (Brazil) and was focus of many investigations, but never regarding its community of endophytic symbionts. During a screening program, an endophytic strain isolated from the V. divergens, was investigated for its potential to show biological activity. The strain was characterized as Microbispora sp. LGMB259 by spore morphology and molecular analyze using nucleotide sequence of the 16S rRNA gene. Strain LGMB259 was cultivated in R5A medium producing metabolites with significant antibacterial activity. The strain produced 4 chemically related ß-carbolines, and 3 Indoles. Compound 1-vinyl-ß-carboline-3-carboxylic acid displayed potent activity against the Gram-positive bacterial strains Micrococcus luteus NRRL B-2618 and Kocuria rosea B-1106, and was highly active against two human cancer cell lines, namely the prostate cancer cell line PC3 and the non-small-cell lung carcinoma cell line A549, with IC50 values of 9.45 and 24.67 µM, respectively. 1-Vinyl-ß-carboline-3-carboxylic acid also showed moderate activity against the yeast Saccharomyces cerevisiae ATCC204508, as well as the phytopathogenic fungi Phyllosticta citricarpa LGMB06 and Colletotrichum gloeosporioides FDC83.
Assuntos
Actinobacteria/metabolismo , Carbolinas/metabolismo , Carbolinas/farmacologia , Indóis/metabolismo , Indóis/farmacologia , Traqueófitas/microbiologia , Actinobacteria/classificação , Actinobacteria/isolamento & purificação , Actinobacteria/ultraestrutura , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Brasil , Carbolinas/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Indóis/química , Concentração Inibidora 50 , Estrutura Molecular , Filogenia , RNA Ribossômico 16S/genéticaRESUMO
Streptomyces spp. are "nature's antibiotic factories" that produce valuable bioactive metabolites, such as the cytotoxic anthracycline polyketides. While the anthracyclines have hundreds of natural and chemically synthesized analogues, much of the chemical diversity stems from enzymatic modifications to the saccharide chains and, to a lesser extent, from alterations to the core scaffold. Previous work has resulted in the generation of a BioBricks synthetic biology toolbox in Streptomyces coelicolor M1152ΔmatAB that could produce aklavinone, 9-epi-aklavinone, auramycinone, and nogalamycinone. In this work, we extended the platform to generate oxidatively modified analogues via two crucial strategies. (i) We swapped the ketoreductase and first-ring cyclase enzymes for the aromatase cyclase from the mithramycin biosynthetic pathway in our polyketide synthase (PKS) cassettes to generate 2-hydroxylated analogues. (ii) Next, we engineered several multioxygenase cassettes to catalyze 11-hydroxylation, 1-hydroxylation, 10-hydroxylation, 10-decarboxylation, and 4-hydroxyl regioisomerization. We also developed improved plasmid vectors and S. coelicolor M1152ΔmatAB expression hosts to produce anthracyclinones. This work sets the stage for the combinatorial biosynthesis of bespoke anthracyclines using recombinant Streptomyces spp. hosts.