6v8g

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GltPh mutant - Y204L A345V V366AGltPh mutant - Y204L A345V V366A

Structural highlights

6v8g is a 3 chain structure with sequence from Pyrococcus horikoshii OT3. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 3.38Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

GLT_PYRHO Sodium-dependent, high-affinity amino acid transporter that mediates aspartate uptake (PubMed:17435767, PubMed:19380583, PubMed:17230192, Ref.11). Has only very low glutamate transport activity (PubMed:19380583, PubMed:17230192). Functions as a symporter that transports one amino acid molecule together with two or three Na(+) ions, resulting in electrogenic transport (PubMed:17435767, PubMed:19380583, Ref.11). Na(+) binding enhances the affinity for aspartate (PubMed:19380583, Ref.11). Mediates Cl(-) flux that is not coupled to amino acid transport; this avoids the accumulation of negative charges due to aspartate and Na(+) symport (PubMed:17435767). In contrast to mammalian homologs, transport does not depend on pH or K(+) ions (PubMed:19380583).[1] [2] [3] [PDB:4P19]

Publication Abstract from PubMed

Membrane transporters mediate cellular uptake of nutrients, signaling molecules, and drugs. Their overall mechanisms are often well understood, but the structural features setting their rates are mostly unknown. Earlier single-molecule fluorescence imaging of the archaeal model glutamate transporter homologue GltPh from Pyrococcus horikoshii suggested that the slow conformational transition from the outward- to the inward-facing state, when the bound substrate is translocated from the extracellular to the cytoplasmic side of the membrane, is rate limiting to transport. Here, we provide insight into the structure of the high-energy transition state of GltPh that limits the rate of the substrate translocation process. Using bioinformatics, we identified GltPh gain-of-function mutations in the flexible helical hairpin domain HP2 and applied linear free energy relationship analysis to infer that the transition state structurally resembles the inward-facing conformation. Based on these analyses, we propose an approach to search for allosteric modulators for transporters.

The high-energy transition state of the glutamate transporter homologue GltPh.,Huysmans GHM, Ciftci D, Wang X, Blanchard SC, Boudker O EMBO J. 2021 Jan 4;40(1):e105415. doi: 10.15252/embj.2020105415. Epub 2020 Nov, 13. PMID:33185289[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Boudker O, Ryan RM, Yernool D, Shimamoto K, Gouaux E. Coupling substrate and ion binding to extracellular gate of a sodium-dependent aspartate transporter. Nature. 2007 Jan 25;445(7126):387-93. Epub 2007 Jan 17. PMID:17230192 doi:10.1038/nature05455
  2. Ryan RM, Mindell JA. The uncoupled chloride conductance of a bacterial glutamate transporter homolog. Nat Struct Mol Biol. 2007 May;14(5):365-71. doi: 10.1038/nsmb1230. Epub 2007 Apr , 15. PMID:17435767 doi:http://dx.doi.org/10.1038/nsmb1230
  3. Ryan RM, Compton EL, Mindell JA. Functional characterization of a Na+-dependent aspartate transporter from Pyrococcus horikoshii. J Biol Chem. 2009 Jun 26;284(26):17540-8. doi: 10.1074/jbc.M109.005926. Epub 2009, Apr 20. PMID:19380583 doi:http://dx.doi.org/10.1074/jbc.M109.005926
  4. Huysmans GHM, Ciftci D, Wang X, Blanchard SC, Boudker O. The high-energy transition state of the glutamate transporter homologue GltPh. EMBO J. 2021 Jan 4;40(1):e105415. doi: 10.15252/embj.2020105415. Epub 2020 Nov, 13. PMID:33185289 doi:http://dx.doi.org/10.15252/embj.2020105415

6v8g, resolution 3.38Å

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OCA