Siderophore-mediated zinc acquisition enhances enterobacterial colonization of the inflamed gut

Abstract

ABSTRACTZinc is an essential cofactor for bacterial metabolism, and manyEnterobacteriaceaeexpress the zinc transporters ZnuABC and ZupT to acquire this metal in the host. Unexpectedly, the probiotic bacteriumEscherichia coliNissle 1917 exhibited appreciable growth in zinc-limited media even when these transporters were deleted. By utilizingin vitroandin vivostudies, as well as native spray metal infusion mass spectrometry and ion identity molecular networking, we discovered that Nissle utilizes yersiniabactin as a zincophore. Indeed, yersiniabactin enables Nissle to scavenge zinc in zinc-limited media, to resist calprotectin-mediated zinc sequestration, and to thrive in the inflamed gut. Moreover, we discovered that yersiniabactin’s affinity for iron or zinc changes in a pH-dependent manner, with higher affinity for zinc as the pH increased. Altogether, we demonstrate that siderophore metal affinity can be influenced by the local environment and reveal a mechanism of zinc acquisition available to many commensal and pathogenicEnterobacteriaceae.