RESUMO
A gene coding for a terpene synthase homolog from Kitasatospora viridis was cloned and expressed in Escherichia coli. The purified recombinant protein possessed sesterterpene synthase activity and efficiently converted geranylfarnesyl diphosphate (GFPP) with 19 % yield into the sesterterpene hydrocarbon sestervirideneâ A. Large scale enzymatic conversions also allowed for the isolation of two side products that are generated with very low yields of ca. 0.1 %. Several derivatives of sestervirideneâ A were obtained by chemical transformations, securing the NMR-based structural assignments. The absolute configuration of sestervirideneâ A was determined by chemical correlation using stereoselectively deuterated precursors and by anomalous dispersion X-ray crystallography. The cyclisation mechanism from GFPP to sestervirideneâ A was extensively studied through isotopic labelling experiments and DFT calculations.
Assuntos
Alquil e Aril Transferases , Streptomycetaceae , Sesterterpenos/química , Streptomycetaceae/metabolismo , Proteínas RecombinantesRESUMO
The marine-derived Streptomyces sp. FIMYZ-003 strain was found to produce novel siderophores with yields negatively correlated with the iron concentration in the medium. Mass spectrometry (MS)-based metabolomics coupled with metallophore assays identified two novel α-hydroxycarboxylate-type siderophores, fradiamines C and D (3 and 4), together with two related known siderophores, fradiamines A and B (1 and 2). Their chemical structures were elucidated by nuclear magnetic resonance (NMR) and MS experiments. The annotation of a putative fra biosynthetic gene cluster enabled us to propose the biosynthetic pathway of fradiamines A-D. Furthermore, the solution-phase iron-binding activity of fradiamines was evaluated using metabolomics, confirming them as general iron scavengers. Fradiamines A-D exhibited Fe(III) binding activity equivalent to that of deferoxamine B mesylate. Growth analysis of pathogenic microbes demonstrated that fradiamine C promoted the growth of Escherichia coli and Staphylococcus aureus, but fradiamines A, B, and D did not. The results indicate that fradiamine C may serve as a novel iron carrier applicable to antibiotic delivery strategies to treat and prevent foodborne pathogens.
Assuntos
Compostos Férricos , Sideróforos , Quelantes , Ferro/metabolismo , Metabolômica , Sideróforos/química , Sideróforos/genética , Sideróforos/metabolismo , Streptomycetaceae/química , Streptomycetaceae/metabolismoRESUMO
The residues of imazamox (IMX) will cause phytotoxicity to subsequent crops after long-term use, and will also pollute the soil and its surrounding environment. This study isolates and identifies two strains of Streptomycetaceae JX02 and JX06 that can effectively degrade IMX. Use response surface method Box-Behnken design to optimize physicochemical parameters. The optimal degradation conditions of strains JX02 and JX06 are obtained and verified: IMX concentration is 150 mg L-1, the initial dosage is 9.9%, 9.1% (OD600 = 0.1), the temperature is 26.4 and 27.5 °C, and pH value is 7.0 and 7.7, respectively. The degradation rates of 150 mg L-1 IMX detected by HPLC within 4 d were 99 and 94%, respectively. After adding strains JX02 and JX06, the half-life of IMX in the soil is shortened to 11 d and 13 d, indicating that Streptomycetaceae had a positive effect on the remediation of soil. It is expected to provide scientific information for the rational use, environmental safety evaluation of IMX, and provide a basis for future research and development of microbial agents.
Assuntos
Poluentes do Solo , Streptomycetaceae , Biodegradação Ambiental , Imidazóis , Solo/química , Poluentes do Solo/metabolismo , Streptomycetaceae/metabolismoRESUMO
Tryptophan 2C methyltransferase (TsrM) methylates C2 of the indole ring of L-tryptophan during biosynthesis of the quinaldic acid moiety of thiostrepton. TsrM is annotated as a cobalamin-dependent radical S-adenosylmethionine (SAM) methylase; however, TsrM does not reductively cleave SAM to the universal 5'-deoxyadenosyl 5'-radical intermediate, a hallmark of radical SAM (RS) enzymes. Herein, we report structures of TsrM from Kitasatospora setae, which are the first structures of a cobalamin-dependent radical SAM methylase. Unexpectedly, the structures show an essential arginine residue that resides in the proximal coordination sphere of the cobalamin cofactor, and a [4Fe-4S] cluster that is ligated by a glutamyl residue and three cysteines in a canonical CXXXCXXC RS motif. Structures in the presence of substrates suggest a substrate-assisted mechanism of catalysis, wherein the carboxylate group of SAM serves as a general base to deprotonate N1 of the tryptophan substrate, facilitating the formation of a C2 carbanion.
Assuntos
Metiltransferases/metabolismo , Metiltransferases/ultraestrutura , Arginina/química , Catálise , Coenzimas , Proteínas Ferro-Enxofre/metabolismo , Metilação , S-Adenosilmetionina , Streptomycetaceae/genética , Streptomycetaceae/metabolismo , Tioestreptona/biossíntese , Triptofano/metabolismo , Vitamina B 12/química , Difração de Raios X/métodosRESUMO
The cell wall is considered an essential component for bacterial survival, providing structural support, and protection from environmental insults. Under normal growth conditions, filamentous actinobacteria insert new cell wall material at the hyphal tips regulated by the coordinated activity of cytoskeletal proteins and cell wall biosynthetic enzymes. Despite the importance of the cell wall, some filamentous actinobacteria can produce wall-deficient S-cells upon prolonged exposure to hyperosmotic stress. Here, we performed cryo-electron tomography and live cell imaging to further characterize S-cell extrusion in Kitasatospora viridifaciens. We show that exposure to hyperosmotic stress leads to DNA compaction, membrane and S-cell extrusion, and thinning of the cell wall at hyphal tips. Additionally, we find that the extrusion of S-cells is abolished in a cytoskeletal mutant strain that lacks the intermediate filament-like protein FilP. Furthermore, micro-aerobic culturing promotes the formation of S-cells in the wild type, but the limited oxygen still impedes S-cell formation in the ΔfilP mutant. These results demonstrate that S-cell formation is stimulated by oxygen-limiting conditions and dependent on functional cytoskeleton remodeling.
Assuntos
Parede Celular/metabolismo , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Pressão Osmótica , Streptomycetaceae/metabolismo , Anaerobiose/fisiologia , Microscopia Crioeletrônica , Proteínas do Citoesqueleto/genética , Citoesqueleto/genética , Tomografia com Microscopia Eletrônica , Filamentos Intermediários/genética , Oxigênio/metabolismo , Microbiologia do Solo , Streptomycetaceae/genéticaRESUMO
Filamentous Actinobacteria are multicellular bacteria with linear replicons. Kitasatospora viridifaciens DSM 40239 contains a linear 7.8 Mb chromosome and an autonomously replicating plasmid KVP1 of 1.7 Mb. Here we show that lysozyme-induced protoplast formation of the multinucleated mycelium of K. viridifaciens drives morphological diversity. Characterisation and sequencing of an individual revertant colony that had lost the ability to differentiate revealed that the strain had not only lost most of KVP1 but also carried deletions in the right arm of the chromosome. Strikingly, the deletion sites were preceded by insertion sequence elements, suggesting that the rearrangements may have been caused by replicative transposition and homologous recombination between both replicons. These data indicate that protoplast formation is a stressful process that can lead to profound genetic changes.
Assuntos
Genoma Bacteriano , Protoplastos , Streptomycetaceae/genética , Elementos de DNA Transponíveis , Heterogeneidade Genética , Plasmídeos , Regeneração , Streptomycetaceae/metabolismoRESUMO
Cyclic dimeric 3'-5' guanosine monophosphate, c-di-GMP, is a ubiquitous second messenger controlling diverse cellular processes in bacteria. In streptomycetes, c-di-GMP plays a crucial role in a complex morphological differentiation by modulating an activity of the pleiotropic regulator BldD. Here we report that c-di-GMP plays a key role in regulating secondary metabolite production in streptomycetes by altering the expression levels of bldD. Deletion of cdgB encoding a diguanylate cyclase in Streptomycesghanaensis reduced c-di-GMP levels and the production of the peptidoglycan glycosyltransferase inhibitor moenomycin A. In contrast to the cdgB mutant, inactivation of rmdB, encoding a phosphodiesterase for the c-di-GMP hydrolysis, positively correlated with the c-di-GMP and moenomycin A accumulation. Deletion of bldD adversely affected the synthesis of secondary metabolites in S. ghanaensis, including the production of moenomycin A. The bldD-deficient phenotype is partly mediated by an increase in expression of the pleiotropic regulatory gene wblA. Genetic and biochemical analyses demonstrate that a complex of c-di-GMP and BldD effectively represses transcription of wblA, thus preventing sporogenesis and sustaining antibiotic synthesis. These results show that manipulation of the expression of genes controlling c-di-GMP pool has the potential to improve antibiotic production as well as activate the expression of silent gene clusters.
Assuntos
Proteínas de Bactérias/genética , Bambermicinas/biossíntese , Produtos Biológicos/metabolismo , GMP Cíclico/análogos & derivados , Proteínas de Ligação a DNA/genética , Fatores de Transcrição/genética , Proteínas de Bactérias/antagonistas & inibidores , GMP Cíclico/genética , GMP Cíclico/metabolismo , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Escherichia coli/genética , Deleção de Genes , Regulação Bacteriana da Expressão Gênica/genética , Nucleotídeos/genética , Peptidoglicano Glicosiltransferase/antagonistas & inibidores , Fósforo-Oxigênio Liases/genética , Sistemas do Segundo Mensageiro/genética , Streptomycetaceae/genética , Streptomycetaceae/metabolismo , Fatores de Transcrição/antagonistas & inibidoresRESUMO
Small cell lung cancer (SCLC) is a severe malignancy with early and widespread metastasis, and novel therapeutic drugs are needed. To identify cytotoxic natural compounds against SCLC, we screened libraries of microbial fermentation broths using several lung cancer cell lines. We found that the actinomycete strain MG372-hF19 produces a compound that has not been isolated from natural sources but previously chemically synthesized, 6-chloro-1H-indole-3-carboxaldehyde (1), and an entirely new compound, named 6-deoxy-α-L-talopyranose 1-(6-chloro-1H-indole-3-carboxylate) (2), together with leptomycins. The molecular formulas of the compounds were established as C9H6ClNO and C15H16ClNO6, respectively, via high-resolution electrospray ionization mass spectrometry, and their structures were determined using detailed NMR. Absolute configurational analysis of the sugar unit of compound 2 revealed that the compound incorporates the rare deoxyhexose 6-deoxy-α-L-talopyranose. Both compounds exhibited weak growth-inhibiting activities against human lung cancer cell lines.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Glicosídeos/química , Streptomycetaceae/metabolismo , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Humanos , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológicoRESUMO
Pyranose 2-oxidase (POx) has long been accredited a physiological role in lignin degradation, but evidence to provide insights into the biochemical mechanisms and interactions is insufficient. There are ample data in the literature on the oxidase and dehydrogenase activities of POx, yet the biological relevance of this duality could not be established conclusively. Here we present a comprehensive biochemical and phylogenetic characterization of a novel pyranose 2-oxidase from the actinomycetous bacterium Kitasatospora aureofaciens (KaPOx) as well as a possible biomolecular synergism of this enzyme with peroxidases using phenolic model substrates in vitro A phylogenetic analysis of both fungal and bacterial putative POx-encoding sequences revealed their close evolutionary relationship and supports a late horizontal gene transfer of ancestral POx sequences. We successfully expressed and characterized a novel bacterial POx gene from K. aureofaciens, one of the putative POx genes closely related to well-known fungal POx genes. Its biochemical characteristics comply with most of the classical hallmarks of known fungal pyranose 2-oxidases, i.e., reactivity with a range of different monosaccharides as electron donors as well as activity with oxygen, various quinones, and complexed metal ions as electron acceptors. Thus, KaPOx shows the pronounced duality of oxidase and dehydrogenase similar to that of fungal POx. We further performed efficient redox cycling of aromatic lignin model compounds between KaPOx and manganese peroxidase (MnP). In addition, we found a Mn(III) reduction activity in KaPOx, which, in combination with its ability to provide H2O2, implies this and potentially other POx as complementary enzymatic tools for oxidative lignin degradation by specialized peroxidases.IMPORTANCE Establishment of a mechanistic synergism between pyranose oxidase and (manganese) peroxidases represents a vital step in the course of elucidating microbial lignin degradation. Here, the comprehensive characterization of a bacterial pyranose 2-oxidase from Kitasatospora aureofaciens is of particular interest for several reasons. First, the phylogenetic analysis of putative pyranose oxidase genes reveals a widespread occurrence of highly similar enzymes in bacteria. Still, there is only a single report on a bacterial pyranose oxidase, stressing the need of closing this gap in the scientific literature. In addition, the relatively small K. aureofaciens proteome supposedly supplies a limited set of enzymatic functions to realize lignocellulosic biomass degradation. Both enzyme and organism therefore present a viable model to study the mechanisms of bacterial lignin decomposition, elucidate physiologically relevant interactions with specialized peroxidases, and potentially realize biotechnological applications.
Assuntos
Proteínas de Bactérias/genética , Desidrogenases de Carboidrato/genética , Peroxidases/genética , Streptomycetaceae/genética , Proteínas de Bactérias/metabolismo , Desidrogenases de Carboidrato/metabolismo , Oxirredução , Oxirredutases/metabolismo , Peroxidases/metabolismo , Streptomycetaceae/enzimologia , Streptomycetaceae/metabolismoRESUMO
Here we report a transcription factor decoy strategy for targeted activation of eight large silent polyketide synthase and non-ribosomal peptide synthetase gene clusters, ranging from 50 to 134 kilobases (kb) in multiple streptomycetes, and characterization of a novel oxazole family compound produced by a 98-kb biosynthetic gene cluster. Owing to its simplicity and ease of use, this strategy can be scaled up readily for discovery of natural products in streptomycetes.
Assuntos
Peptídeo Sintases/genética , Policetídeo Sintases/genética , Fatores de Transcrição/biossíntese , Regulação da Expressão Gênica/genética , Família Multigênica/fisiologia , Peptídeo Sintases/fisiologia , Policetídeo Sintases/fisiologia , Streptomycetaceae/metabolismoRESUMO
The search for new compounds effective against Mycobacterium tuberculosis is still a priority in medicine. The evaluation of microorganisms isolated from non-conventional locations offers an alternative to look for new compounds with antimicrobial activity. Endophytes have been successfully explored as source of bioactive compounds. In the present work we studied the nature and antimycobacterial activity of a compound produced by Streptomyces scabrisporus, an endophyte isolated from the medicinal plant Amphipterygium adstringens. The active compound was detected as the main secondary metabolite present in organic extracts of the streptomycete and identified by NMR spectroscopic data as steffimycin B (StefB). This anthracycline displayed a good activity against M. tuberculosis H37Rv ATCC 27294 strain, with MIC100 and SI values of 7.8 µg/mL and 6.42, respectively. When tested against the rifampin mono resistant M. tuberculosis Mtb-209 pathogen strain, a better activity was observed (MIC100 of 3.9 µg/mL), suggesting a different action mechanism of StefB from that of rifampin. Our results supported the endophyte Streptomyces scabrisporus as a good source of StefB for tuberculosis treatment, as this anthracycline displayed a strong bactericidal effect against M. tuberculosis, one of the oldest and more dangerous human pathogens causing human mortality.
Assuntos
Antraciclinas/farmacologia , Sapindaceae/metabolismo , Anacardiaceae , Antraciclinas/isolamento & purificação , Antraciclinas/metabolismo , Anti-Infecciosos/farmacologia , Antituberculosos , Endófitos/isolamento & purificação , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Plantas Medicinais/metabolismo , Sapindaceae/toxicidade , Streptomycetaceae/metabolismoRESUMO
Bafilomycins produced by Kitasatospora cheerisanensis KCTC- 2395 belong to the 16-membered macrolactone family plecomacrolide antibiotics. Bafilomycin B1 contains 2-amino- 3-hydroxycyclopent-2-enone (C5N), a five membered ring, which gets condensed via an amide linkage to bafilomycin polyketide. To study the biosynthetic pathway of C5N during bafilomycin biosynthesis in K. cheerisanensis KCTC2395, we attempted the functional analysis of two putative genes, encoding 5-aminolevulinic acid synthase (ALAS) and acyl- CoA ligase (ACL). The amplified putative genes for ALAS and ACL were cloned into the E. coli expression vector pET- 32a(+) plasmid, following which the soluble recombinant ALAS and ACL proteins were purified through nickel-affinity column chromatography. Through HPLC analysis of the enzyme reaction mixture, we confirmed the products of putative ALAS and ACL reaction as 5-aminolevulinic acid (5-ALA) and 5-ALA-CoA, respectively. The optimal pH for the putative ALAS reaction was 7.5, and for putative ACL reaction was 7.0, as confirmed by the colorimetric assay. Furthermore, pyridoxal 5'-phosphate (PLP) was found to be an essential cofactor in the putative ALAS reaction, and ATP was a cofactor for the putative ACL catalysis. Finally, we also confirmed that the simultaneous treatment of putative ACL and putative ALAS enzymes resulted in the production of C5N compound from 5-ALA.
Assuntos
5-Aminolevulinato Sintetase/metabolismo , Vias Biossintéticas/genética , Coenzima A Ligases/metabolismo , Ciclopentanos/metabolismo , Streptomycetaceae/enzimologia , Streptomycetaceae/metabolismo , 5-Aminolevulinato Sintetase/genética , Clonagem Molecular , Coenzima A Ligases/genética , Coenzimas/análise , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos , Concentração de Íons de Hidrogênio , Plasmídeos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Streptomycetaceae/genéticaRESUMO
ß-Carboline alkaloids and related compounds show a broad spectrum of biological activities. We previously identified new members of the ß-carboline alkaloid family by using an engineered Kitasatospora setae strain and a heterologous Streptomyces host expressing the plausible biosynthetic genes, including the hypothetical gene kse_70640 (kslB). Here, we elucidated the chemical structure of a new tetrahydro-ß-carboline compound (named kitasetalic acid) that appeared in a heterologous Streptomyces host expressing the kslB gene alone. Kitasetalic acid suppressed the expression of glucose-regulated protein 78 (GRP78) without inducing cell death. This is the first report to show that a tetrahydro-ß-carboline compound regulates the expression of the GRP78 protein in cancer cell lines.
Assuntos
Carbolinas/metabolismo , Engenharia Genética , Glucose/farmacologia , Streptomycetaceae/metabolismo , Carbolinas/química , Carbolinas/farmacologia , Linhagem Celular , Chaperona BiP do Retículo Endoplasmático , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Estrutura Molecular , Streptomycetaceae/genéticaRESUMO
BACKGROUND/PURPOSE: In this study, an acidophilic actinobacteria strain was used as a novel reducing agent for a single-step synthesis of nanostructure silver particles. We used a Streptacidiphilus durhamensis HGG16n isolate for efficient synthesis of bioactive silver nanoparticles [bio(AgNPs)] in an inexpensive, eco-friendly, and nontoxic manner. The obtained bio(AgNPs) exhibited unique physicochemical and biochemical properties. METHODS: Structural, morphological, and optical properties of the synthesized biocolloids were characterized by spectroscopy, dynamic light scattering, and electron microscopy approaches. The antimicrobial activity was evaluated using the well- and disc-diffusion methods. RESULTS: The obtained crystalline structure and stable biosynthesized silver nanoparticles ranged in size from 8 nm to 48 nm and were mostly spherical in shape. Antimicrobial assays of the silver nanoparticles against pathogenic bacteria showed the highest antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus, and Proteus mirabilis, followed by Escherichia coli, Klebsiella pneumoniae, and Bacillus subtilis. Moreover, the synergistic effect of bio(AgNPs) with various commercially available antibiotics was also evaluated. CONCLUSION: These results provide insight into the development of new antimicrobial agents along with synergistic enhancement of the antibacterial mechanism against clinical bacteria.
Assuntos
Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Nanopartículas Metálicas/química , Prata/metabolismo , Prata/farmacologia , Streptomycetaceae/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Proteus mirabilis/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacosRESUMO
Streptomycetes are known for their inherent ability to produce pharmaceutically relevant secondary metabolites. Discovery of medically useful, yet novel compounds has become a great challenge due to frequent rediscovery of known compounds and a consequent decline in the number of relevant clinical trials in the last decades. A paradigm shift took place when the first whole genome sequences of streptomycetes became available, from which silent or "cryptic" biosynthetic gene clusters (BGCs) were discovered. Cryptic BGCs reveal a so far untapped potential of the microorganisms for the production of novel compounds, which has spurred new efforts in understanding the complex regulation between primary and secondary metabolism. This new trend has been accompanied with development of new computational resources (genome and compound mining tools), generation of various high-quality omics data, establishment of molecular tools, and other strain engineering strategies. They all come together to enable systems metabolic engineering of streptomycetes, allowing more systematic and efficient strain development. In this review, the authors present recent progresses within systems metabolic engineering of streptomycetes for uncovering their hidden potential to produce novel compounds and for the improved production of secondary metabolites.
Assuntos
Engenharia Metabólica/tendências , Streptomycetaceae/metabolismo , Biologia de Sistemas , Metabolismo Secundário/genética , Streptomycetaceae/genéticaRESUMO
Belactosins and cystargolides are natural product proteasome inhibitors from Actinobacteria. Both feature dipeptidic backbones and a unique ß-lactone building block. Herein, we present a detailed investigation of their biosynthesis. Identification and analysis of the corresponding gene clusters indicated that both compounds are assembled by rare single-enzyme amino acid ligases. Feeding experiments with isotope-labeled precursors and inâ vitro biochemistry showed that the formation of the ß-lactone warhead is unprecedented and reminiscent of leucine biosynthesis, and that it involves the action of isopropylmalate synthase homologues.
Assuntos
Dipeptídeos/metabolismo , Lactonas/química , Peptídeos/metabolismo , Inibidores de Proteassoma/síntese química , Streptomycetaceae/metabolismo , Aminoácidos/metabolismo , Genoma Bacteriano , Peptídeos e Proteínas de Sinalização Intercelular , Ligases/genética , Ligases/metabolismo , Espectroscopia de Ressonância Magnética , Família Multigênica , Streptomycetaceae/genética , Espectrometria de Massas em TandemRESUMO
The genus Kitasatospora was proposed in 1982. Although Kitasatospora strains resemble Streptomyces strains in morphology, they are clearly different in cell-wall composition, as they contain both LL- and meso-diaminopimelic acid. Aerial and submerged spores contain LL-, while vegetative and submerged mycelia contain mainly meso- in their cell walls. Currently, 23 species have been validly proposed. Members of the genus Kitasatospora form a tight cluster and represent a legitimate genus distinct from Streptomyces on the basis of phylogenetic analysis of 16S rRNA gene sequences. A variety of biologically active compounds have been found from Kitasatospora strains and structures of these compounds are extremely diverse. Genome sequences of 15 strains published so far are about 7-9 Mb in size and contain many genes governing secondary metabolites.
Assuntos
RNA Ribossômico 16S/genética , Metabolismo Secundário/genética , Streptomycetaceae/genética , Parede Celular/química , Genoma Bacteriano , Filogenia , Análise de Sequência de RNA , Especificidade da Espécie , Streptomyces/classificação , Streptomyces/genética , Streptomycetaceae/classificação , Streptomycetaceae/metabolismoRESUMO
Tyropeptins are new proteasome inhibitors isolated from the culture broth of Kitasatospora sp. MK993-dF2. Tyropeptins permeate cell membranes, inhibit intracellular proteasomes and reduce the degradation of ubiquitinated proteins in mammalian cells. We performed structure-based drug design and structure-activity relationship studies on tyropeptin derivatives to obtain valuable information of derivatives. Among the synthesized tyropeptin derivatives, some boronic acid derivatives exhibited potent antitumor effects against human multiple myeloma. In this review, we summarize the discovery of tyropeptins and the development of tyropeptin derivatives.
Assuntos
Dipeptídeos/isolamento & purificação , Desenho de Fármacos , Streptomycetaceae/metabolismo , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Dipeptídeos/química , Dipeptídeos/farmacologia , Humanos , Complexo de Endopeptidases do Proteassoma , Inibidores de Proteassoma/química , Inibidores de Proteassoma/isolamento & purificação , Inibidores de Proteassoma/farmacologia , Relação Estrutura-AtividadeRESUMO
Actinomycetes, such as mycobacteria and streptomycetes, synthesize α-glucan with α-1,4 linkages and α-1,6 branching to help evade immune responses and to store carbon. α-Glucan is thought to resemble glycogen except for having shorter constituent linear chains. However, the fine structure of α-glucan and how it can be defined by the maltosyl transferase GlgE and branching enzyme GlgB were not known. Using a combination of enzymolysis and mass spectrometry, we compared the properties of α-glucan isolated from actinomycetes with polymer synthesized in vitro by GlgE and GlgB. We now propose the following assembly mechanism. Polymer synthesis starts with GlgE and its donor substrate, α-maltose 1-phosphate, yielding a linear oligomer with a degree of polymerization (â¼16) sufficient for GlgB to introduce a branch. Branching involves strictly intrachain transfer to generate a C chain (the only constituent chain to retain its reducing end), which now bears an A chain (a nonreducing end terminal branch that does not itself bear a branch). GlgE preferentially extends A chains allowing GlgB to act iteratively to generate new A chains emanating from B chains (nonterminal branches that themselves bear a branch). Although extension and branching occur primarily with A chains, the other chain types are sometimes extended and branched such that some B chains (and possibly C chains) bear more than one branch. This occurs less frequently in α-glucans than in classical glycogens. The very similar properties of cytosolic and capsular α-glucans from Mycobacterium tuberculosis imply GlgE and GlgB are sufficient to synthesize them both.
Assuntos
Glucanos/química , Glucanos/metabolismo , Glucosiltransferases/metabolismo , Mycobacterium/metabolismo , Streptomycetaceae/metabolismo , Fosfatos Açúcares/metabolismo , Eletroforese Capilar , Espectroscopia de Ressonância Magnética , Mycobacterium/classificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
GOAL: To study in vitro the antinematicide activity of soil streptomycetes metabolite and bioformulations based on them against root-knot, cyst and leaf nematodes of species. METHODS: Action of streptomycetes metabolites and their bioformulations were determined in vitro against larvae at two age of root-knot nematode M incognita (Kofoid & White, 1919) Chitwood 1949 and sugar beet cyst nematode H. schachtii A. Schmidt 1871, and leaf nematodes ofAphlenchoides genus by cultivation them in solutions of biomass ethanol extracts separate individual components metabolites and bioformulations during 24 hours. Nematicide and nematistatic effects of the substances were evaluated by the change in the motility activity of the nematodes. RESULTS: Soil streptomycetes S. violaceus IMV Ac-5027, S. averinitilis IMV Ac-5015 and metabolite bioformulations based on them (Violar, Aver- com and Avercom-nova, respectively) showed significant nematicidal activity against plant pathogenic nematodes M incognita and H. schachtii. The biomass extracts of S. avermiti- lis IMV Ac-5015 and S. violaceus IMV Ac-5027 caused 100 % death of nematodes, and S. netropsis IMV Ac-5025 caused only 75 % mortality during 24 hours of action. Using an antibiotic complex from S. violaceus IMV Ac-5027 was divided on six fractions that were different from the avermectin complex. Purified fractions of individual antibiotic complex of S. violaceus IMV Ac-5 027 have a negative impact against the root-knot nematode M incognita. The highest nematicidal activity showed fractions #4 and #5 since their efficiency was over 90 % after a 0.5 hours of action. Nematicidal efficiency of fractions ## 1, 2, 3 and 6 remained between 72.6-86.2 % during 24 hours of action. Fractions 4 and 5 showed high nematicidal effectiveness against leaf nematodes of Aphelenchoides genus where 90-95 % level of helminthes death was observed after 4 hours of action. Among created complex metabolite bioformulations Avercom-nova was the most effective which caused 100 % mortality of nematodes M incognita and H. schachtii after 24 hours of action. Bioformu- lation Violar caused 96.6-96.8 and 95.2-97.0 % of death of nematodes M incognita and H. schachtii, after 24 hours of action. Phytovit based on S. netropsis IMV Ac-5025 showed low nematicide activity against of nematodes, which did not exceed 15.2-18.4 % of their death after 24 hour of action. Bioformulations based on streptomycetes metabolites did not inferior to chemical insecticide Konfidor Maxi, which caused the death of 93.3-94.6 % nematodes at doses recommended by the manufacturer. CONCLUSION: Soil streptomycetes S. violaceus IV Ac-5027 and S. avermitilis IMV Ac-5015 are promising producers for creation of bioformulations with nematicidal activity against plant-parasitic nematode of M incoenita and H. schachtii.