Structure and function of an Arabidopsis thaliana sulfate transporter

Nat Commun. 2021 Jul 22;12(1):4455. doi: 10.1038/s41467-021-24778-2.


Plant sulfate transporters (SULTR) mediate absorption and distribution of sulfate (SO42-) and are essential for plant growth; however, our understanding of their structures and functions remains inadequate. Here we present the structure of a SULTR from Arabidopsis thaliana, AtSULTR4;1, in complex with SO42- at an overall resolution of 2.8 Å. AtSULTR4;1 forms a homodimer and has a structural fold typical of the SLC26 family of anion transporters. The bound SO42- is coordinated by side-chain hydroxyls and backbone amides, and further stabilized electrostatically by the conserved Arg393 and two helix dipoles. Proton and SO42- are co-transported by AtSULTR4;1 and a proton gradient significantly enhances SO42- transport. Glu347, which is ~7 Å from the bound SO42-, is required for H+-driven transport. The cytosolic STAS domain interacts with transmembrane domains, and deletion of the STAS domain or mutations to the interface compromises dimer formation and reduces SO42- transport, suggesting a regulatory function of the STAS domain.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anion Transport Proteins / chemistry*
  • Anion Transport Proteins / genetics
  • Anion Transport Proteins / metabolism*
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / chemistry*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Binding Sites / genetics
  • Cryoelectron Microscopy
  • Glutamic Acid / chemistry
  • Models, Molecular
  • Protein Interaction Domains and Motifs
  • Protein Multimerization
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Static Electricity
  • Sulfate Transporters / chemistry*
  • Sulfate Transporters / genetics
  • Sulfate Transporters / metabolism*
  • Sulfates / metabolism


  • Anion Transport Proteins
  • Arabidopsis Proteins
  • Recombinant Proteins
  • Sulfate Transporters
  • Sulfates
  • Sultr4;1 protein, Arabidopsis
  • Glutamic Acid