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E Recio

Publications and source records attributed to E Recio.

4 recordsLinked to original sources
PubMed2004

Polyene macrolide antibiotic biosynthesis.

Polyenes constitute a large class of natural metabolites produced by giant multifunctional enzymes in a process resembling fatty acid biosynthesis. Like fatty acids, polyene macrolides and other polyketides are assembled by decarboxylative condensations of simple carboxylic acids. But while fatty acid intermediates are fully reduced, polyene macrolide intermediates suffer the suppression of reduction or dehydration reactions at given biosynthetic steps. In the last years, much progress has been made in our understanding of the linear and modular organization of the gene clusters, and the enzymes encoded by them, responsible for the biosynthesis of these macrocyclic metabolites. This know-how about the rules that govern polyene chain growth has provided the basis for the first rational manipulations of these fascinating systems for the production of engineered derivatives and promises a new era of novel polyene development, which will hopefully yield new molecules with improved pharmacological properties.

Antifungal Agents↗
PubMed2003

Characterization of the ask-asd operon in aminoethoxyvinylglycine-producing Streptomyces sp. NRRL 5331.

The first two genes of the threonine pathway, ask and asd, were cloned and sequenced from the aminoethoxyvinylglycine-producing Streptomyces sp. NRRL 5331. The two genes are organized in a bicistronic operon. ask, encoding the apartokinase (ASK), is located upstream from asd. The presence of a ribosome-binding site within the ask sequence suggests that this open reading frame encodes two overlapping proteins. The formation of both subunits of the aspartokinase from a single gene was studied using antibodies raised against the C-terminal end of the aspartokinase subunits. Disruption of asd results in a significant decrease of aminoethoxyvinylglycine production, thus supporting the involvement of the ask-asd operon in the biosynthesis of this metabolite. This is the first report in which a gene cluster for the first two steps of aminoethoxyvinylglycine biosynthesis is characterized.

Amino Acid Motifs↗
PubMed2001

Engineered biosynthesis of novel polyenes: a pimaricin derivative produced by targeted gene disruption in Streptomyces natalensis.

BACKGROUND: The post-polyketide synthase biosynthetic tailoring of polyene macrolides usually involves oxidations catalysed by cytochrome P450 monooxygenases (P450s). Although members from this class of enzymes are common in macrolide biosynthetic gene clusters, their specificities vary considerably toward the substrates utilised and the positions of the hydroxyl functions introduced. In addition, some of them may yield epoxide groups. Therefore, the identification of novel macrolide monooxygenases with activities toward alternative substrates, particularly epoxidases, is a fundamental aspect of the growing field of combinatorial biosynthesis. The specific alteration of these activities should constitute a further source of novel analogues. We investigated this possibility by directed inactivation of one of the P450s belonging to the biosynthetic gene cluster of an archetype polyene, pimaricin. RESULTS: A recombinant mutant of the pimaricin-producing actinomycete Streptomyces natalensis produced a novel pimaricin derivative, 4,5-deepoxypimaricin, as a major product. This biologically active product resulted from the phage-mediated targeted disruption of the gene pimD, which encodes the cytochrome P450 epoxidase that converts deepoxypimaricin into pimaricin. The 4,5-deepoxypimaricin has been identified by mass spectrometry and nuclear magnetic resonance following high-performance liquid chromatography purification. CONCLUSIONS: We have demonstrated that PimD is the epoxidase responsible for the conversion of 4,5-deepoxypimaricin to pimaricin in S. natalensis. The metabolite accumulated by the recombinant mutant, in which the epoxidase has been knocked out, constitutes the first designer polyene obtained by targeted manipulation of a polyene biosynthetic gene cluster. This novel epoxidase could prove to be valuable for the introduction of epoxy substituents into designer macrolides.

Antifungal Agents↗