Unique structural features in an Nramp metal transporter impart substrate-specific proton cotransport and a kinetic bias to favor import.

ABSTRACT: Natural resistance-associated macrophage protein (Nramp) transporters enable uptake of essential transition metal micronutrients in numerous biological contexts. These proteins are believed to function as secondary transporters that harness the electrochemical energy of proton gradients by "coupling" proton and metal transport. Here we use the Deinococcus radiodurans (Dra) Nramp homologue, for which we have determined crystal structures in multiple conformations, to investigate mechanistic details of metal and proton transport. We untangle the proton-metal coupling behavior of DraNramp into two distinct phenomena: ΔpH stimulation of metal transport rates and metal stimulation of proton transport. Surprisingly, metal type influences substrate stoichiometry, leading to manganese-proton cotra

SUBMITTER: Bozzi AT 

PROVIDER: S-EPMC6888756 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature