Transcriptional Regulation of Agmatine Deiminase Pathway in Enterococcus faecalis

CRISTIAN A. SUÁREZ; MARTÍN ESPARIZ; VICTOR BLANCATO; CHRISTIAN MAGNI

Potrero de los Funes

Congreso; 47th Annual Meeting Argentine Society for Biochemistry and Molecular Biology y XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Enterococcus faecalis are found as nonstarter lactic acid bacteria ina wide variety of cheeses mostly produced from raw milk. Thismicroorganism can be potentially hazardous to human health dueto their pathogenicity or by the production of toxic compounds likebiogenic amines. E. faecalis is able to metabolize agmatine withputrescine, ammonia and ATP as final products by means ofagmatine deiminase pathway.In this work we demonstrate that the transcriptional regulatorAguR is essential for the agmatine metabolism in E. faecalis, sincean AguR defective strain is unable to grow in presence of agmatine.Moreover, as a result of ß-galactosidase and Northern blot analysiswe could demonstrate that agmatine is inducing the agu genecluster. There are some differences in the mechanisms underlyingagmatine metabolizing gene expression in E. faecalis with therelated bacterium Streptococcus mutants. In the later, the agucluster is induced under acid or high temperature conditions,whereas in E. faecalis its expression showed to be independent ofpH and temperature. Finally, we investigated the role of cataboliterepression on the activity of the AguR controlled promoter,showing that this promoter is regulated by a CcpA independentmechanism.