RELATIONSHIP BETWEEN PURINE METABOLISM AND ANTIBIOTIC PRODUCTION Streptomyces coelicolor

LAURA NAVONE; PAULA CASATI; HUGO GRAMAJO; EDUARDO JOSE RODRIGUEZ

Puerto Madryn

Congreso; 46 Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2010

Sociedad Argentina de Bioquímica y Biología Vegetal

Purine metabolism in soil bacteria such as Streptomyces plays animportant role in recycling nitrogen compounds from deathorganisms. However, only a parcial pathway for catabolism of GTPand ATP to allantoin has been reported. In this work we study a set ofgenes (sco6243, sco6247, sco6248) that is involved in the finalconversion of allantoin to glyoxylate, ammonium and malate. Inturn, we have also identified a negative transcriptional regulator forthis set of genes, AllRStr, which is similar to the regulator protein ofthe allantoin pathway from E. coli, AllR. sco6243, sco6247 andsco6248 codify a putative malate syntase, allantoinase andallantoicase protein respectively. Growth analyses of mutant strainsfor each of these genes in minimal media containing purines orallantoin as the sole carbon and nitrogen source have demostratedthat these genes are essencial for cell survival under theseconditions.Inactivation of AllRStr increases the expression of allantoinpathway genes and strongly impairs antibiotic production. We arecurrently disrupting these genes in an allRStr mutant background todetermine if impaired antibiotic production is due to theoverexpression of this metabolic pathway. This results may wellsuggest that availability of precursors for synthesis of (p)ppGpp oracetyl-CoA are a check point for the production of secondarymetabolites in Streptomyces.