Cryo-EM structures of a pentameric ligand-gated ion channel in liposomes
Detergents and lipid nanodiscs affect the cryo-EM structures of pentameric ligand-gated ion channels (pLGICs) including ELIC. To determine the structure of a pLGIC in a membrane environment that supports ion channel function, we performed single particle cryo-EM of ELIC in liposomes. ELIC activation...
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eLife Sciences Publications Ltd
2025-07-01
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| Online Access: | https://elifesciences.org/articles/106728 |
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| author | Vikram Dalal Brandon K Tan Hanrui Xu Wayland WL Cheng |
| author_facet | Vikram Dalal Brandon K Tan Hanrui Xu Wayland WL Cheng |
| author_sort | Vikram Dalal |
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| description | Detergents and lipid nanodiscs affect the cryo-EM structures of pentameric ligand-gated ion channels (pLGICs) including ELIC. To determine the structure of a pLGIC in a membrane environment that supports ion channel function, we performed single particle cryo-EM of ELIC in liposomes. ELIC activation and desensitization were confirmed in liposomes with a stopped-flow thallium flux assay. Using WT ELIC and a non-desensitizing mutant (ELIC5), we captured resting, activated, and desensitized structures at high resolution. In the desensitized structure, the ion conduction pore has a constriction at the 9’ leucine of the pore-lining M2 helix, indicating that 9’ is the desensitization gate in ELIC. The agonist-bound structures of ELIC in liposomes are distinct from those in nanodiscs. In general, the transmembrane domain is more loosely packed in liposomes compared to nanodiscs. It has been suggested that large nanodiscs are superior for supporting membrane protein function. However, ELIC localizes to the rim of large circularized nanodiscs, and structures of ELIC in large nanodiscs deviate from the liposome structures more than those in small nanodiscs. Using liposomes for cryo-EM structure determination of a pLGIC increases our confidence that the structures are snapshots of functional states. |
| format | Article |
| id | doaj-art-adaea4f5463a4cc1ba36aea71d610163 |
| institution | DOAJ |
| issn | 2050-084X |
| language | English |
| publishDate | 2025-07-01 |
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| spelling | doaj-art-adaea4f5463a4cc1ba36aea71d6101632025-08-20T03:11:57ZengeLife Sciences Publications LtdeLife2050-084X2025-07-011410.7554/eLife.106728Cryo-EM structures of a pentameric ligand-gated ion channel in liposomesVikram Dalal0Brandon K Tan1Hanrui Xu2Wayland WL Cheng3https://orcid.org/0000-0002-9529-9820Department of Anesthesiology, Washington University School of Medicine, St Louis, United StatesDepartment of Anesthesiology, Washington University School of Medicine, St Louis, United StatesDepartment of Anesthesiology, Washington University School of Medicine, St Louis, United StatesDepartment of Anesthesiology, Washington University School of Medicine, St Louis, United StatesDetergents and lipid nanodiscs affect the cryo-EM structures of pentameric ligand-gated ion channels (pLGICs) including ELIC. To determine the structure of a pLGIC in a membrane environment that supports ion channel function, we performed single particle cryo-EM of ELIC in liposomes. ELIC activation and desensitization were confirmed in liposomes with a stopped-flow thallium flux assay. Using WT ELIC and a non-desensitizing mutant (ELIC5), we captured resting, activated, and desensitized structures at high resolution. In the desensitized structure, the ion conduction pore has a constriction at the 9’ leucine of the pore-lining M2 helix, indicating that 9’ is the desensitization gate in ELIC. The agonist-bound structures of ELIC in liposomes are distinct from those in nanodiscs. In general, the transmembrane domain is more loosely packed in liposomes compared to nanodiscs. It has been suggested that large nanodiscs are superior for supporting membrane protein function. However, ELIC localizes to the rim of large circularized nanodiscs, and structures of ELIC in large nanodiscs deviate from the liposome structures more than those in small nanodiscs. Using liposomes for cryo-EM structure determination of a pLGIC increases our confidence that the structures are snapshots of functional states.https://elifesciences.org/articles/106728ligand-gated ion channelcryo-EMliposomesnanodiscs |
| spellingShingle | Vikram Dalal Brandon K Tan Hanrui Xu Wayland WL Cheng Cryo-EM structures of a pentameric ligand-gated ion channel in liposomes eLife ligand-gated ion channel cryo-EM liposomes nanodiscs |
| title | Cryo-EM structures of a pentameric ligand-gated ion channel in liposomes |
| title_full | Cryo-EM structures of a pentameric ligand-gated ion channel in liposomes |
| title_fullStr | Cryo-EM structures of a pentameric ligand-gated ion channel in liposomes |
| title_full_unstemmed | Cryo-EM structures of a pentameric ligand-gated ion channel in liposomes |
| title_short | Cryo-EM structures of a pentameric ligand-gated ion channel in liposomes |
| title_sort | cryo em structures of a pentameric ligand gated ion channel in liposomes |
| topic | ligand-gated ion channel cryo-EM liposomes nanodiscs |
| url | https://elifesciences.org/articles/106728 |
| work_keys_str_mv | AT vikramdalal cryoemstructuresofapentamericligandgatedionchannelinliposomes AT brandonktan cryoemstructuresofapentamericligandgatedionchannelinliposomes AT hanruixu cryoemstructuresofapentamericligandgatedionchannelinliposomes AT waylandwlcheng cryoemstructuresofapentamericligandgatedionchannelinliposomes |