The copYAZ operon functions in copper efflux, biofilm formation, genetic transformation and stress tolerance in Streptococcus mutans (original) (raw)

ABSTRACTIn bacteria, copper homeostasis is closely monitored to ensure proper cellular functions while avoiding cell damage. Most Gram-positive bacteria utilize thecopYABZoperon for copper homeostasis, wherecopAandcopBencode copper-transporting P-type ATPases, whereascopYandcopZregulate the expression of thecopoperon.Streptococcus mutansis a biofilm-forming oral pathogen that harbors a putative copper-transportingcopYAZoperon. Here, we characterized the role ofcopYAZoperon in the physiology ofS. mutansand delineated the mechanisms of copper-induced toxicity in this bacterium. We observed that copper induced toxicity inS. mutanscells by generating oxidative stress and disrupting their membrane potential. Deletion of thecopYAZoperon inS. mutansstrain UA159 resulted in reduced cell viability under copper, acid, and oxidative stress relative to the viability of the wild type under these conditions. Furthermore, the ability ofS. mutansto form biofilms and develop genetic competence was i...