Coupled binding mechanism of three sodium ions and aspartate in the glutamate transporter homologue Glt Tk

Nat Commun. 2016 Nov 10;7:13420. doi: 10.1038/ncomms13420.

Abstract

Glutamate transporters catalyse the thermodynamically unfavourable transport of anionic amino acids across the cell membrane by coupling it to the downhill transport of cations. This coupling mechanism is still poorly understood, in part because the available crystal structures of these transporters are of relatively low resolution. Here we solve crystal structures of the archaeal transporter GltTk in the presence and absence of aspartate and use molecular dynamics simulations and binding assays to show how strict coupling between the binding of three sodium ions and aspartate takes place.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Transport System X-AG / chemistry
  • Amino Acid Transport System X-AG / genetics
  • Amino Acid Transport System X-AG / metabolism*
  • Archaeal Proteins / chemistry
  • Archaeal Proteins / genetics
  • Archaeal Proteins / metabolism*
  • Aspartic Acid / chemistry
  • Aspartic Acid / metabolism*
  • Binding Sites / genetics
  • Crystallography, X-Ray
  • Kinetics
  • Molecular Dynamics Simulation
  • Protein Binding
  • Protein Domains
  • Sequence Homology, Amino Acid
  • Sodium / chemistry
  • Sodium / metabolism*
  • Thermococcus / genetics
  • Thermococcus / metabolism
  • Thermodynamics

Substances

  • Amino Acid Transport System X-AG
  • Archaeal Proteins
  • Aspartic Acid
  • Sodium