Crystal structures of a ZIP zinc transporter reveal a binuclear metal center in the transport pathway.

ABSTRACT: Zrt/Irt-like proteins (ZIPs) play fundamental roles in metal metabolism/homeostasis and are broadly involved in numerous physiological and pathological processes. The lack of high-resolution structure of the ZIPs hinders understanding of the metal transport mechanism. We report two crystal structures of a prokaryotic ZIP in lipidic cubic phase with bound metal substrates (Cd²⁺ at 2.7 Å and Zn²⁺ at 2.4 Å). The structures revealed a novel 3+2+3TM architecture and an inward-open conformation occluded at the extracellular side. Two metal ions were trapped halfway through the membrane, unexpectedly forming a binuclear metal center. The Zn²⁺-substituted structure suggested asymmetric functions of the two metal-binding sites and also revealed a route for zinc rele

SUBMITTER: Zhang T 

PROVIDER: S-EPMC5573306 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature