Crystal structure of a SLC11 (NRAMP) transporter reveals the basis for transition-metal ion transport.

TitleCrystal structure of a SLC11 (NRAMP) transporter reveals the basis for transition-metal ion transport.
Publication TypeJournal Article
Year of Publication2014
AuthorsEhrnstorfer, I. A., E. R. Geertsma, E. Pardon, J. Steyaert, and R. Dutzler
JournalNat Struct Mol Biol
Volume21
Issue11
Pagination990-6
Date Published2014 Nov
ISSN1545-9985
KeywordsAmino Acid Sequence, Amino Acid Transport Systems, Bacterial Proteins, Binding Sites, Cadmium, Cation Transport Proteins, Cations, Divalent, Conserved Sequence, Crystallography, X-Ray, Escherichia coli, Gene Expression, Humans, Ion Transport, Iron, Manganese, Models, Molecular, Molecular Sequence Data, Protein Binding, Protein Conformation, Recombinant Proteins, Staphylococcus, Structural Homology, Protein, Substrate Specificity, Transcription Factors
Abstract

Members of the SLC11 (NRAMP) family transport iron and other transition-metal ions across cellular membranes. These membrane proteins are present in all kingdoms of life with a high degree of sequence conservation. To gain insight into the determinants of ion selectivity, we have determined the crystal structure of Staphylococcus capitis DMT (ScaDMT), a close prokaryotic homolog of the family. ScaDMT shows a familiar architecture that was previously identified in the amino acid permease LeuT. The protein adopts an inward-facing conformation with a substrate-binding site located in the center of the transporter. This site is composed of conserved residues, which coordinate Mn2+, Fe2+ and Cd2+ but not Ca2+. Mutations of interacting residues affect ion binding and transport in both ScaDMT and human DMT1. Our study thus reveals a conserved mechanism for transition-metal ion selectivity within the SLC11 family.

DOI10.1038/nsmb.2904
Alternate JournalNat. Struct. Mol. Biol.
PubMed ID25326704
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