Crystal structure of a nitrate transporter

Experimental Data Snapshot

  • Resolution: 3.25 Å
  • R-Value Free: 0.307 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.238 

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Crystal structure of the plant dual-affinity nitrate transporter NRT1.1.

Sun, J.Bankston, J.R.Payandeh, J.Hinds, T.R.Zagotta, W.N.Zheng, N.

(2014) Nature 507: 73-77

  • DOI: https://doi.org/10.1038/nature13074
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Nitrate is a primary nutrient for plant growth, but its levels in soil can fluctuate by several orders of magnitude. Previous studies have identified Arabidopsis NRT1.1 as a dual-affinity nitrate transporter that can take up nitrate over a wide range of concentrations. The mode of action of NRT1.1 is controlled by phosphorylation of a key residue, Thr 101; however, how this post-translational modification switches the transporter between two affinity states remains unclear. Here we report the crystal structure of unphosphorylated NRT1.1, which reveals an unexpected homodimer in the inward-facing conformation. In this low-affinity state, the Thr 101 phosphorylation site is embedded in a pocket immediately adjacent to the dimer interface, linking the phosphorylation status of the transporter to its oligomeric state. Using a cell-based fluorescence resonance energy transfer assay, we show that functional NRT1.1 dimerizes in the cell membrane and that the phosphomimetic mutation of Thr 101 converts the protein into a monophasic high-affinity transporter by structurally decoupling the dimer. Together with analyses of the substrate transport tunnel, our results establish a phosphorylation-controlled dimerization switch that allows NRT1.1 to uptake nitrate with two distinct affinity modes.

  • Organizational Affiliation

    1] Department of Pharmacology, Box 357280, University of Washington, Seattle, Washington 98195, USA [2] Howard Hughes Medical Institute, Box 357280, University of Washington, Seattle, Washington 98195, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Nitrate transporter 1.1
A, B
599Arabidopsis thalianaMutation(s): 0 
Gene Names: NRT1.1CHL1NRT1At1g12110F12F1.1T28K15_13
Membrane Entity: Yes 
Find proteins for Q05085 (Arabidopsis thaliana)
Explore Q05085 
Go to UniProtKB:  Q05085
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ05085
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.25 Å
  • R-Value Free: 0.307 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.238 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.8α = 90
b = 188.465β = 90
c = 262.848γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
PHENIXmodel building
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-03-05
    Type: Initial release
  • Version 1.1: 2014-03-12
    Changes: Database references