The Initiation of GTP Hydrolysis by the G-Domain of FeoB: Insights from a Transition-State Complex Structure

Abstract

The polytopic membrane protein FeoB is a ferrous iron transporter in prokaryotes. The protein contains a potassium-activated GTPase domain that is essential in regulating the import of iron and conferring virulence to many disease-causing bacteria. However, the mechanism by which the G-domain of FeoB hydrolyzes GTP is not well understood. In particular, it is not yet known how the pivotal step in GTP hydrolysis is achieved: alignment of a catalytic water molecule. In the current study, the crystal structure of the soluble domains from Streptococcus thermophilus FeoB (NFeoB(St)) in complex with the activating potassium ion and a transition-state analogue, GDP⋅AlF(4) (-), reveals a novel mode ..