Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site.
Glutamate homeostasis in the brain is maintained by glutamate transporter mediated accumulation. Impaired transport is associated with several neurological disorders, including stroke and amyotrophic lateral sclerosis. Crystal structures of the homolog transporter GltPh from Pyrococcus horikoshii re...
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2015-10-01
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| Series: | PLoS Computational Biology |
| Online Access: | https://doi.org/10.1371/journal.pcbi.1004551 |
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| author | SanthoshKannan Venkatesan Kusumika Saha Azmat Sohail Walter Sandtner Michael Freissmuth Gerhard F Ecker Harald H Sitte Thomas Stockner |
| author_facet | SanthoshKannan Venkatesan Kusumika Saha Azmat Sohail Walter Sandtner Michael Freissmuth Gerhard F Ecker Harald H Sitte Thomas Stockner |
| author_sort | SanthoshKannan Venkatesan |
| collection | DOAJ |
| description | Glutamate homeostasis in the brain is maintained by glutamate transporter mediated accumulation. Impaired transport is associated with several neurological disorders, including stroke and amyotrophic lateral sclerosis. Crystal structures of the homolog transporter GltPh from Pyrococcus horikoshii revealed large structural changes. Substrate uptake at the atomic level and the mechanism of ion gradient conversion into directional transport remained enigmatic. We observed in repeated simulations that two local structural changes regulated transport. The first change led to formation of the transient Na2 sodium binding site, triggered by side chain rotation of T308. The second change destabilized cytoplasmic ionic interactions. We found that sodium binding to the transiently formed Na2 site energized substrate uptake through reshaping of the energy hypersurface. Uptake experiments in reconstituted proteoliposomes confirmed the proposed mechanism. We reproduced the results in the human glutamate transporter EAAT3 indicating a conserved mechanics from archaea to humans. |
| format | Article |
| id | doaj-art-3d2c2a2e354f436ea7bcde927f57c869 |
| institution | Kabale University |
| issn | 1553-734X 1553-7358 |
| language | English |
| publishDate | 2015-10-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Computational Biology |
| spelling | doaj-art-3d2c2a2e354f436ea7bcde927f57c8692025-08-20T03:46:42ZengPublic Library of Science (PLoS)PLoS Computational Biology1553-734X1553-73582015-10-011110e100455110.1371/journal.pcbi.1004551Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site.SanthoshKannan VenkatesanKusumika SahaAzmat SohailWalter SandtnerMichael FreissmuthGerhard F EckerHarald H SitteThomas StocknerGlutamate homeostasis in the brain is maintained by glutamate transporter mediated accumulation. Impaired transport is associated with several neurological disorders, including stroke and amyotrophic lateral sclerosis. Crystal structures of the homolog transporter GltPh from Pyrococcus horikoshii revealed large structural changes. Substrate uptake at the atomic level and the mechanism of ion gradient conversion into directional transport remained enigmatic. We observed in repeated simulations that two local structural changes regulated transport. The first change led to formation of the transient Na2 sodium binding site, triggered by side chain rotation of T308. The second change destabilized cytoplasmic ionic interactions. We found that sodium binding to the transiently formed Na2 site energized substrate uptake through reshaping of the energy hypersurface. Uptake experiments in reconstituted proteoliposomes confirmed the proposed mechanism. We reproduced the results in the human glutamate transporter EAAT3 indicating a conserved mechanics from archaea to humans.https://doi.org/10.1371/journal.pcbi.1004551 |
| spellingShingle | SanthoshKannan Venkatesan Kusumika Saha Azmat Sohail Walter Sandtner Michael Freissmuth Gerhard F Ecker Harald H Sitte Thomas Stockner Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site. PLoS Computational Biology |
| title | Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site. |
| title_full | Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site. |
| title_fullStr | Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site. |
| title_full_unstemmed | Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site. |
| title_short | Refinement of the Central Steps of Substrate Transport by the Aspartate Transporter GltPh: Elucidating the Role of the Na2 Sodium Binding Site. |
| title_sort | refinement of the central steps of substrate transport by the aspartate transporter gltph elucidating the role of the na2 sodium binding site |
| url | https://doi.org/10.1371/journal.pcbi.1004551 |
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