Allantoin metabolism in Streptomyces coelicolor: crosstalk with antibiotic production

LAURA NAVONE; CASATI P.; HUGO GRAMAJO; EDUARDO JOSE RODRIGUEZ

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2012

Here we studied the allantoin metabolism in the biotechnologically important strain Streptomyces coelicolor. This bacterium is characterized by a complex life cycle, including programmed cell death. In submerged cultures of S. coelicolor, growth arrest corresponds to a transition phase from a first vegetative mycelium to a second differentiated mycelium. Remarkably, antibiotics are produced by this second mycelium and depend on growth condition such us cell density and probably assimilation of cell components released by cell lysis. Our results have shown that the catabolism of allantoin in S. coelicolor causes a decrease of antibiotic production. We have identified and characterized proteins involved in the allantoin pathway including allantoinase, allantoicase and malate syntase. Genetic studies allowed us to validate this as the only pathway to metabolize allantoin in S. coelicolor. Phenotypic analysis of allantoinase or allantoicase mutant strains showed that the catabolism of allantoin and release of ammonium is probably the cause of the decreased antibiotic production. Furthermore, metabolic and proteomic studies revealed a downregulation of nitrogen uptake enzymes, accumulation of urea and several aminoacids, suggesting that in these conditions nitrogen is in excess. These observations link the impairment of antibiotic production with an unbalance in nitrogen metabolism.