ABSTRACT
Genome sequencing and bioinformatic analysis have identified numerous cryptic gene clusters that have the potential to produce novel natural products. Within this work, we identified a cryptic type II PKS gene cluster (skt) from Streptomyces sp. Tü 6314. Facilitated by linear plus linear homologous recombination-mediated recombineering (LLHR), we directly cloned the skt gene cluster using the Streptomyces site-specific integration vector pSET152. Direct cloning allowed for rapid heterologous expression in Streptomyces coelicolor, leading to the identification and structural characterization of six polyketides (three known compounds and new streptoketides), four of which exhibit anti-HIV activities. Our study shows that the pSET152 vector can be directly used for LLHR, expanding the Rec/ET direct cloning toolbox and providing the possibility for rapid heterologous expression of gene clusters from Streptomyces.
Subject(s)
Gene Expression Regulation, Bacterial , Multigene Family , Polyketide Synthases/genetics , Polyketides/isolation & purification , Streptomyces/enzymology , Animals , Antiviral Agents/chemistry , Antiviral Agents/isolation & purification , Antiviral Agents/pharmacology , Cell Line , Chromatography, High Pressure Liquid/methods , Cloning, Molecular , Microbial Sensitivity Tests , Polyketides/chemistry , Polyketides/pharmacology , Spectrum Analysis/methods , Streptomyces/geneticsABSTRACT
A new octaketide named fogacin (1) was isolated from Streptomyces sp. (strain Tü 6319). Furthermore two shunt metabolites, SEK4b (2) and anhydroSEK4b (3), were detected and identified as non-enzymatically cyclized products of polyketide intermediates built during the biosynthesis of actinorhodin. SEK4b (2) as well as anhydroSEK4b (3) were previously described as metabolites of genetically engineered strains.
Subject(s)
Anti-Bacterial Agents/chemistry , Macrolides/chemistry , Streptomyces/chemistry , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Circular Dichroism , Macrolides/isolation & purification , Macrolides/pharmacology , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Optical Rotation , Spectrometry, Mass, Electrospray Ionization , Spectrophotometry, UltravioletABSTRACT
A new xanthone compound named retymicin (1) was isolated together with galtamycin B (2) and saquayamycin Z (3), new members of the galtamycin and saquayamycin families, respectively, and the new lumichrome derivative 1-(alpha-ribofuranosyl)-lumichrome (4) from Micromonospora strain Tü 6368, isolated from a soil sample collected in Romania. Retymicin, galtamycin B and saquayamycin Z show cytostatic effects to various human tumor cell lines whereas saquayamycin Z is also active against Gram-positive bacteria.
Subject(s)
Anthracyclines/isolation & purification , Anthracyclines/pharmacology , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Antibiotics, Antineoplastic/isolation & purification , Antibiotics, Antineoplastic/pharmacology , Micromonospora/chemistry , Xanthones/isolation & purification , Bacteria/drug effects , Carbohydrate Sequence , Cell Line, Tumor , Chemical Phenomena , Chemistry, Physical , Chromatography, High Pressure Liquid , Drug Screening Assays, Antitumor , Fermentation , Humans , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Molecular Sequence Data , Romania , Soil Microbiology , Xanthones/pharmacologyABSTRACT
A detailed screening of the secondary metabolite pattern from Micromonospora sp. strain Tü 6368 resulted in the isolation of ten compounds belonging to five different structural families. The structures of the novel compounds 1-(alpha-ribofuranosyl)-lumichrome (3), retymicin (7), galtamycin B (11) and saquayamycin Z (14) were assigned by spectroscopic methods and chemical transformations. This strain fits our hypothesis that the metabolite analysis of biosynthetically talented strains leads readily to novel compounds.
