IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Effect of primary metabolic pathways over triacylglycerol accumulation and antibiotic production in Streptomyces coelicolor
Autor/es:
LAURA NAVONE, HUGO GRAMAJO AND EDUARDO RODRÍGUEZ
Lugar:
Puerto Vallarta
Reunión:
Conferencia; 16 International Symposium on the Biology of Actinomycetes; 2011
Resumen:
Purine metabolism in soil bacteria such as Streptomyces plays an important role in recycling of the carbon and nitrogen components of purines generated during nucleotide turnover. The purine salvage pathway and the catabolism of GTP and ATP to allantoin have been previously reported in Streptomyces. In this work, we have studied the metabolism of allantoin to malate, its conversion into pyruvate and the role of this pathway in antibiotic and triacylglycerol production in S. coelicolor. We have identified a negative regulatory element AllR, and genes encoding allantoinase, allantoicase and malate syntase proteins which are involved in the conversion of allantoin to ammonium, 3-P-glycerate and malate. Growth analyses of mutant strains for each of these genes in minimal media containing purines or allantoin as the sole carbon and nitrogen source showed that this is the only pathway to metabolize allantoin in S. colelicolor. Inactivation of the negative regulator AllR increases the expression of the allantoin pathway genes, and strongly impairs antibiotic production. Proteome analysis of allR mutant strain has shown increased expression of proteins involved in the tricarboxylic acid cycle, biosynthesis of aminoacids and metabolism of purines among others. On the other hand, we have characterized two anaplerotic malic enzymes that catalyze the oxidative decarboxylation of malate into pyruvate with the reduction of NAD or NADP. A malic enzyme double mutant strain showed a pronounced decrease in antibiotic and triacylglycerol production under different carbon sources tested. Metabolite analysis evidenced the accumulation of TCA-precursors in the double mutant strain. Together, our results presented here expand our understanding the relevance of primary metabolic pathways and the connection with secondary metabolism in Streptomyces.