Magnesium uptake by CorA is essential for viability of the gastric pathogen Helicobacter pylori.

We show here that Mg(2+) acquisition by CorA is essential for Helicobacter pylori in vitro, as corA mutants did not grow in media without Mg(2+) supplementation. Complementation analysis performed with an Escherichia coli corA mutant revealed that H. pylori CorA transports nickel and cobalt in addition to Mg(2+). However, Mg(2+) is the dominant CorA substrate, as the corA mutation affected neither cobalt and nickel resistance nor nickel induction of urease in H. pylori. The drastic Mg(2+) requirement (20 mM) of H. pylori corA mutants indicates that CorA plays a key role in the adaptation to the low-Mg(2+) conditions predominant in the gastric environment.