ENTEROBACTIN ROLES IN COPPER TOLERANCE AND TOXICITY

PERALTA DR; BULACIO GIL N; FARIZANO JV; CORBALÁN NS; POMARES MF; CARAM DI SANTO C; RUBIO MOLINA AC; DE CRISTOBAL RE; ZENOFF AM; VINCENT PA; ADLER C

Congreso; SAIB - SAMIGE Joint meeting 2021 on line; 2021

SAIB - SAMIGE

The ability of siderophores to play roles beyond iron acquisition has been recently proven for many of them and evidencecontinues to grow. An earlier work showed that the siderophore enterobactin is able to increase copper toxicity by reducingCu2+ to Cu+, which diffuses more easily across cell membranes. Copper toxicity is multifaceted and involves the formation ofreactive oxygen species, mismetallation of enzymes and possibly other mechanisms. Given that we previously reported on thecapacity of enterobactin to alleviate oxidative stress caused by variousstressors other than copper, we considered the possibilitythat the siderophore could play a dual role regarding copper toxicity. In this work we found that the absence of enterobactinincreased E. coli sensitivity to copper and that low concentrations of the siderophore had a protective effect by reducingreactive oxygen species (ROS). We also observed that copper induced the expression and production of the siderophore,counteracting the downregulation effect of iron. Interestingly, when we used enterobactin in high concentrations, cells becameparticularly sensitive to copper due to the Cu2+ to Cu+reduction, which led to cell death.