1. Biochemistry and Chemical Biology
  2. Structural Biology and Molecular Biophysics
Download icon

Mechanistic basis of the inhibition of SLC11/NRAMP-mediated metal ion transport by bis-isothiourea substituted compounds

  1. Cristina Manatschal  Is a corresponding author
  2. Jonai Pujol-Giménez
  3. Marion Poirier
  4. Jean-Louis Reymond
  5. Matthias A Hediger
  6. Raimund Dutzler  Is a corresponding author
  1. University of Zürich, Switzerland
  2. University of Bern, Switzerland
Research Article
  • Cited 2
  • Views 953
  • Annotations
Cite this article as: eLife 2019;8:e51913 doi: 10.7554/eLife.51913

Abstract

In humans, the divalent metal-ion transporter-1 (DMT1) mediates the transport of ferrous iron across the apical membrane of enterocytes. Hence, its inhibition could be beneficial for the treatment of iron overload disorders. Here we characterize the interaction of aromatic bis-isothiourea-substituted compounds with human DMT1 and its prokaryotic homologue EcoDMT. Both transporters are inhibited by a common competitive mechanism with potencies in the low micromolar range. The crystal structure of EcoDMT in complex with a brominated derivative defines the binding of the inhibitor to an extracellular pocket of the transporter in direct contact with residues of the metal ion coordination site, thereby interfering with substrate loading and locking the transporter in its outward-facing state. Mutagenesis and structure-activity relationships further support the observed interaction mode and reveal species-dependent differences between pro- and eukaryotic transporters. Together, our data provide the first detailed mechanistic insight into the pharmacology of SLC11/NRAMP transporters.

Article and author information

Author details

  1. Cristina Manatschal

    Department of Biochemistry, University of Zürich, Zürich, Switzerland
    For correspondence
    c.manatschal@bioc.uzh.ch
    Competing interests
    The authors declare that no competing interests exist.
  2. Jonai Pujol-Giménez

    Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9951-1390
  3. Marion Poirier

    Department of Chemistry and Biochemisty, University of Bern, Bern, Switzerland
    Competing interests
    The authors declare that no competing interests exist.
  4. Jean-Louis Reymond

    Department of Chemistry and Biochemisty, University of Bern, Bern, Switzerland
    Competing interests
    The authors declare that no competing interests exist.
  5. Matthias A Hediger

    Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
    Competing interests
    The authors declare that no competing interests exist.
  6. Raimund Dutzler

    Department of Biochemistry, University of Zürich, Zürich, Switzerland
    For correspondence
    dutzler@bioc.uzh.ch
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2193-6129

Funding

Swiss National Science Foundation (NCCR TransCure)

  • Jean-Louis Reymond
  • Matthias A Hediger
  • Raimund Dutzler

Swiss National Science Foundation (SNF grant 310030_182272)

  • Matthias A Hediger

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. László Csanády, Semmelweis University, Hungary

Publication history

  1. Received: September 16, 2019
  2. Accepted: November 22, 2019
  3. Accepted Manuscript published: December 5, 2019 (version 1)
  4. Version of Record published: December 17, 2019 (version 2)

Copyright

© 2019, Manatschal et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 953
    Page views
  • 182
    Downloads
  • 2
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

Further reading

    1. Biochemistry and Chemical Biology
    2. Structural Biology and Molecular Biophysics
    Eric D Hoffer et al.
    Research Article Updated

    Modifications in the tRNA anticodon loop, adjacent to the three-nucleotide anticodon, influence translation fidelity by stabilizing the tRNA to allow for accurate reading of the mRNA genetic code. One example is the N1-methylguanosine modification at guanine nucleotide 37 (m1G37) located in the anticodon loop andimmediately adjacent to the anticodon nucleotides 34, 35, 36. The absence of m1G37 in tRNAPro causes +1 frameshifting on polynucleotide, slippery codons. Here, we report structures of the bacterial ribosome containing tRNAPro bound to either cognate or slippery codons to determine how the m1G37 modification prevents mRNA frameshifting. The structures reveal that certain codon–anticodon contexts and the lack of m1G37 destabilize interactions of tRNAPro with the P site of the ribosome, causing large conformational changes typically only seen during EF-G-mediated translocation of the mRNA-tRNA pairs. These studies provide molecular insights into how m1G37 stabilizes the interactions of tRNAPro with the ribosome in the context of a slippery mRNA codon.

    1. Biochemistry and Chemical Biology
    Eric M Jones et al.
    Tools and Resources

    In humans, the >800 G protein-coupled receptors (GPCRs) are responsible for transducing diverse chemical stimuli to alter cell state, and are the largest class of drug targets. Their myriad structural conformations and various modes of signaling make it challenging to understand their structure and function. Here we developed a platform to characterize large libraries of GPCR variants in human cell lines with a barcoded transcriptional reporter of G-protein signal transduction. We tested 7,800 of 7,828 possible single amino acid substitutions to the beta-2 adrenergic receptor (β2AR) at four concentrations of the agonist isoproterenol. We identified residues specifically important for β2AR signaling, mutations in the human population that are potentially loss of function, and residues that modulate basal activity. Using unsupervised learning, we resolve residues critical for signaling, including all major structural motifs and molecular interfaces. We also find a previously uncharacterized structural latch spanning the first two extracellular loops that is highly conserved across Class A GPCRs and is conformationally rigid in both the inactive and active states of the receptor. More broadly, by linking deep mutational scanning with engineered transcriptional reporters, we establish a generalizable method for exploring pharmacogenomics, structure and function across broad classes of drug receptors.