Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Structural basis of the excitatory amino acid transporter 3 substrate recognition.
Journal, issue, pages	bioRxiv, Year 2024
Publish date	Sep 8, 2024
Authors	Biao Qiu / Olga Boudker /
PubMed Abstract	Excitatory amino acid transporters (EAATs) reside on cell surfaces and uptake substrates, including L-glutamate, L-aspartate, and D-aspartate, using ion gradients. Among five EAATs, EAAT3 is the only ...Excitatory amino acid transporters (EAATs) reside on cell surfaces and uptake substrates, including L-glutamate, L-aspartate, and D-aspartate, using ion gradients. Among five EAATs, EAAT3 is the only isoform that can efficiently transport L-cysteine, a substrate for glutathione synthesis. Recent work suggests that EAAT3 also transports the oncometabolite R-2-hydroxyglutarate (R-2HG). Here, we examined the structural basis of substrate promiscuity by determining the cryo-EM structures of EAAT3 bound to different substrates. We found that L-cysteine binds to EAAT3 in thiolate form, and EAAT3 recognizes different substrates by fine-tuning local conformations of the coordinating residues. However, using purified human EAAT3, we could not observe R-2HG binding or transport. Imaging of EAAT3 bound to L-cysteine revealed several conformational states, including an outward-facing state with a semi-open gate and a disrupted sodium-binding site. These structures illustrate that the full gate closure, coupled with the binding of the last sodium ion, occurs after substrate binding. Furthermore, we observed that different substrates affect how the transporter distributes between a fully outward-facing conformation and intermediate occluded states on a path to the inward-facing conformation, suggesting that translocation rates are substrate-dependent.
External links	bioRxiv / PubMed:39282329 / PubMed Central
Methods	EM (single particle)
Resolution	2.58 - 3.07 Å
Structure data	46586 9d66 EMDB-46586, PDB-9d66: Human excitatory amino acid transporter 3 (EAAT3) with bound L-Aspartate in an intermediate outward facing state Method: EM (single particle) / Resolution: 2.98 Å EMDB-46587: EAAT3 in 200 mM NaCl and 10 mM R-2-hydroxyglutarate buffer at OFS. Method: EM (single particle) / Resolution: 3.07 Å 46588 9d67 EMDB-46588, PDB-9d67: Human excitatory amino acid transporter 3 (EAAT3) with bound D-Aspartate in an intermediate outward facing state Method: EM (single particle) / Resolution: 2.87 Å 46589 9d68 EMDB-46589, PDB-9d68: Human excitatory amino acid transporter 3 (EAAT3) with bound L-Cysteine in an outward facing state Method: EM (single particle) / Resolution: 2.58 Å 46590 9d69 EMDB-46590, PDB-9d69: Human excitatory amino acid transporter 3 (EAAT3) with bound L-Cysteine in an intermediate outward facing state (slight upper position) Method: EM (single particle) / Resolution: 2.99 Å 46591 9d6a EMDB-46591, PDB-9d6a: Human excitatory amino acid transporter 3 (EAAT3) with bound L-Cysteine in an intermediate outward facing state Method: EM (single particle) / Resolution: 2.6 Å EMDB-46592: Human excitatory amino acid transporter 3 (EAAT3) monomer in 200 mM NaCl, 10 mM L-Cysteine at IFS Method: EM (single particle) / Resolution: 2.94 Å
Chemicals	ChemComp-ASP: ASPARTIC ACID ChemComp-NA: Unknown entry ChemComp-HG: Unknown entry ChemComp-HOH: WATER ChemComp-DAS: D-ASPARTIC ACID ChemComp-CYS: CYSTEINE
Source	homo sapiens (human)
Keywords	TRANSPORT PROTEIN / EAAT3 / L-Asp / iOFS / human EAAT3 / D-Asp / Cysteine / OFS / semi-open / iOFS-upper / PROTEIN TRANSPORT / iOFS-star