RESUMO
Aromatic prenylated metabolites have important biological roles and activities in all living organisms. Compared to their importance in all domains of life, we know relatively little about their substrate scopes and metabolic functions. Here, we describe a new UbiA-like prenyltransferase (Ptase) Ubi-297 encoded in a conserved operon of several bacterial taxa, including marine Flavobacteria and the genus Sacchromonospora. In silico analysis of Ubi-297 homologs indicated that members of this Ptase group are composed of several transmembrane α-helices and carry a conserved and distinct aspartic-rich Mg2+-binding domain. We heterologously produced UbiA-like Ptases from the bacterial genera Maribacter, Zobellia, and Algoriphagus in Escherichia coli. Investigation of their substrate scope uncovered the preferential farnesylation of quinoline derivatives, such as 8-hydroxyquinoline-2-carboxylic acid (8-HQA) and quinaldic acid. The results of this study provide new insights into the abundance and diversity of Ptases in marine Flavobacteria and beyond.
RESUMO
Modular biosynthetic machineries such as polyketide synthases (PKSs) or nonribosomal peptide synthetases (NRPSs) give rise to a vast structural diversity of bioactive metabolites indispensable in the treatment of cancer or infectious diseases. Here, we provide evidence for different evolutionary processes leading to the diversification of modular NRPSs and thus, their respective products. Discovery of a novel lipo-octapeptide family from Pseudomonas, the virginiafactins, and detailed structure elucidation of closely related peptides, the cichofactins and syringafactins, allowed retracing recombinational diversification of the respective NRPS genes. Bioinformatics analyses allowed us to spot an evolutionary snapshot of these processes, where recombination occurred both within the same and between different biosynthetic gene clusters. Our systems feature a recent diversification process, which may represent a typical paradigm to variations in modular biosynthetic machineries.
RESUMO
Investigating microbial interactions from an ecological perspective is a particularly fruitful approach to unveil both new chemistry and bioactivity. Microbial predator-prey interactions in particular rely on natural products as signal or defense molecules. In this context, we identified a grazing-resistant Pseudomonas strain, isolated from the bacterivorous amoeba Dictyostelium discoideum. Genome analysis of this bacterium revealed the presence of two biosynthetic gene clusters that were found adjacent to each other on a contiguous stretch of the bacterial genome. Although one cluster codes for the polyketide synthase producing the known antibiotic mupirocin, the other cluster encodes a nonribosomal peptide synthetase leading to the unreported cyclic lipopeptide jessenipeptin. We describe its complete structure elucidation, as well as its synergistic activity against methicillin-resistant Staphylococcus aureus, when in combination with mupirocin. Both biosynthetic gene clusters are regulated by quorum-sensing systems, with 3-oxo-decanoyl homoserine lactone (3-oxo-C10-AHL) and hexanoyl homoserine lactone (C6-AHL) being the respective signal molecules. This study highlights the regulation, richness, and complex interplay of bacterial natural products that emerge in the context of microbial competition.
Assuntos
Produtos Biológicos/farmacologia , Dictyostelium/fisiologia , Sinergismo Farmacológico , Mupirocina/farmacologia , Pseudomonas/metabolismo , Percepção de Quorum/fisiologia , Infecções Estafilocócicas/tratamento farmacológico , 4-Butirolactona/análogos & derivados , 4-Butirolactona/fisiologia , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Genoma Bacteriano , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Infecções Estafilocócicas/metabolismo , Infecções Estafilocócicas/microbiologiaRESUMO
Bacterial defense mechanisms have evolved to protect bacteria against predation by nematodes, predatory bacteria, or amoebae. We identified novel bacterial alkaloids (pyreudiones A-D) that protect the producer, Pseudomonas fluorescens HKI0770, against amoebal predation. Isolation, structure elucidation, total synthesis, and a proposed biosynthetic pathway for these structures are presented. The generation of P. fluorescens gene-deletion mutants unable to produce pyreudiones rendered the bacterium edible to a variety of soil-dwelling amoebae.
Assuntos
Alcaloides/farmacologia , Amoeba/efeitos dos fármacos , Pseudomonas fluorescens/química , Alcaloides/química , Alcaloides/metabolismo , Pseudomonas fluorescens/genética , Pseudomonas fluorescens/metabolismoRESUMO
Sulfa drugs, such as sulfonilamide and dapsone, are classical antibiotics that have been in clinical use worldwide. Despite the relatively simple architectures, practically no natural products are known to feature such aromatic sulfonamide or diarylsulfone substructures. We report the unexpected discovery of three fully unprecedented, sulfonyl-bridged alkaloid dimers (sulfadixiamycins A-C) from recombinant Streptomyces species harboring the entire xiamycin biosynthesis gene cluster. Sulfadixiamycins exhibit moderate antimycobacterial activities and potent antibiotic activities even against multidrug-resistant bacteria. Gene inactivation, complementation, and biotransformation experiments revealed that a flavin-dependent enzyme (XiaH) plays a key role in sulfadixiamycin biosynthesis. XiaH mediates a radical-based, three-component reaction involving two equivalents of xiamycin and sulfur dioxide, which is reminiscent of radical styrene/SO2 copolymerization.
Assuntos
Antibacterianos/biossíntese , Flavoproteínas/metabolismo , Sesquiterpenos/metabolismo , Streptomyces/metabolismo , Sulfonamidas/metabolismo , Sulfonas/metabolismo , Dióxido de Enxofre/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Sesquiterpenos/química , Sesquiterpenos/farmacologia , Streptomyces/efeitos dos fármacos , Relação Estrutura-Atividade , Sulfonamidas/química , Sulfonas/química , Dióxido de Enxofre/químicaRESUMO
Enzyme quartet: Isolation of the first sulfur-bearing intermediate of the gliotoxin pathway in Aspergillus fumigatus and successful inâ vitro conversion of the bisglutathione adduct into an intact epidithiodiketopiperazine by a four-enzyme cascade (including glutamyltransferase GliK and dipeptidase GliJ) revealed an outstanding adaptation of a primary metabolic pathway into natural product biosynthesis that is widespread in fungi.