RESUMO
Siderophores, such as enterobactin (Ent), are small molecules that can be selectively imported into bacteria along with iron by cognate transporters. Siderophore conjugates are thus a promising strategy for delivering functional reagents into bacteria. In this work, we present an easy-to-perform, one-pot chemoenzymatic synthesis of functionalized monoglucosylated enterobactin (MGE). When functionalized MGE is conjugated to a rhodamine fluorophore, which affords RhB-Glc-Ent, it can selectively label Gram-negative bacteria that utilize Ent, including some E. coli strains and P. aeruginosa. V. cholerae, a bacterium that utilizes linearized Ent, can also be weakly targeted. Moreover, the targeting is effective under iron-limiting but not iron-rich conditions. Our results suggest that the RhB-Glc-Ent probe is sensitive not only to the bacterial strain but also to the iron condition in the environment.
Assuntos
Enterobactina/análogos & derivados , Escherichia coli/isolamento & purificação , Pseudomonas aeruginosa/isolamento & purificação , Proteínas de Bactérias/metabolismo , Cromatografia Líquida de Alta Pressão , Enterobactina/síntese química , Enterobactina/metabolismo , Escherichia coli/metabolismo , Glucosiltransferases/metabolismo , Glicosilação , Glicosiltransferases/metabolismo , Espectrometria de Massas , Microscopia , Pseudomonas aeruginosa/metabolismo , Rodaminas/químicaRESUMO
Siderophores are small molecules used to specifically transport iron into bacteria via related receptors. By adapting siderophores and hijacking their pathways, we may discover an efficient and selective way to target microbes. Herein, we report the synthesis of a siderophore-fluorophore conjugate VF-FL derived from vibrioferrin (VF). Using flow cytometry and fluorescence microscopy, the probe selectively labeled vibrios, including V. parahaemolyticus, V. cholerae, and V. vulnificus, even in the presence of other species such as S. aureus and E. coli. The labeling is siderophore-related and both iron-limited conditions and the siderophore moiety are required. The competitive relationship between VF-FL and VF in vibrios implies an unreported VF-related transport mechanism in V. cholerae and V. vulnificus. These studies demonstrate that the siderophore scaffold provides a method to selectively target microbes expressing cognate receptors under iron-limited conditions.