{"corpus_id":1474239,"paper_sha":"450ed41a43833d873222336bf4e5d1b16fd8dbed","doi":"10.1085/JGP.115.3.269","arxiv_id":null,"pmid":10694255,"pmcid":"2217209","mag_id":2141494494,"dblp_id":null,"acl_id":null,"title":"The Barium Site in a Potassium Channel by X-Ray Crystallography","year":2000,"publication_date":"2000-03-01","venue":"The Journal of General Physiology","journal":{"name":"The Journal of General Physiology","pages":"269 - 272","volume":"115"},"journal_issn":null,"journal_title":null,"publication_types":["JournalArticle"],"pubmed_pub_types":["Journal Article","Research Support, Non-U.S. Gov't","Research Support, U.S. Gov't, P.H.S."],"s2_fields_of_study":["Biology","Medicine","Chemistry"],"reference_count":17,"citation_count":202,"influential_citation_count":11,"is_open_access":true,"arxiv_categories":null,"arxiv_license":null,"arxiv_journal_ref":null,"mesh_headings":[{"d":"Bacterial Proteins","mj":true,"ui":"D001426"},{"d":"Barium","mj":false,"qs":[{"q":"metabolism","mj":false,"ui":"Q000378"},{"q":"pharmacology","mj":true,"ui":"Q000494"}],"ui":"D001464"},{"d":"Binding Sites","mj":false,"ui":"D001665"},{"d":"Crystallography, X-Ray","mj":false,"ui":"D018360"},{"d":"Ion Channel Gating","mj":false,"qs":[{"q":"drug effects","mj":false,"ui":"Q000187"},{"q":"physiology","mj":false,"ui":"Q000502"}],"ui":"D015640"},{"d":"Potassium Channels","mj":false,"qs":[{"q":"chemistry","mj":true,"ui":"Q000737"},{"q":"metabolism","mj":false,"ui":"Q000378"}],"ui":"D015221"},{"d":"Protein Structure, Secondary","mj":false,"ui":"D017433"},{"d":"Protein Structure, Tertiary","mj":false,"ui":"D017434"}],"chemicals":[{"n":"Bacterial Proteins","ui":"D001426","reg":"0"},{"n":"Potassium Channels","ui":"D015221","reg":"0"},{"n":"prokaryotic potassium channel","ui":"C107790","reg":"0"},{"n":"Barium","ui":"D001464","reg":"24GP945V5T"}],"comments_corrections":null,"source_flags":5,"s2_open_access_pdf_url":"https://rupress.org/jgp/article-pdf/115/3/269/1146811/gp-8137.pdf","s2_open_access_landing_url":"https://www.semanticscholar.org/paper/450ed41a43833d873222336bf4e5d1b16fd8dbed","s2_open_access_license":"CCBYNCSA","s2_open_access_status":"BRONZE","pmc_open_access_pdf_url":null,"pmc_open_access_landing_url":null,"pmc_open_access_license":null,"pmc_open_access_status":null,"unpaywall_open_access_pdf_url":null,"unpaywall_open_access_landing_url":null,"unpaywall_open_access_license":null,"unpaywall_open_access_status":null,"abstract":"X-ray diffraction data were collected from frozen crystals (100°K) of the KcsA K+ channel equilibrated with solutions containing barium chloride. Difference electron density maps (Fbarium − Fnative, 5.0 Å resolution) show that Ba2+ resides at a single location within the selectivity filter. The Ba2+ blocking site corresponds to the internal aspect (adjacent to the central cavity) of the “inner ion” position where an alkali metal cation is found in the absence of the blocking Ba2+ ion. The location of Ba2+ with respect to Rb+ ions in the pore is in good agreement with the findings on the functional interaction of Ba2+ with K+ (and Rb+) in Ca2+-activated K+ channels (Neyton, J., and C. Miller. 1988. J. Gen. Physiol. 92:549–567). Taken together, these structural and functional data imply that at physiological ion concentrations a third ion may interact with two ions in the selectivity filter, perhaps by entering from one side and displacing an ion on the opposite side.","claims":[{"public_id":"cl_52c068b66b27e78c28de779bc956e752","status":"active","text":"At physiological ion concentrations, a third ion may interact with two ions in the selectivity filter by entering from one side and displacing an ion on the opposite side.","confidence":0.87,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/claims/cl_52c068b66b27e78c28de779bc956e752"},{"public_id":"cl_348c77aa6bedafc923350f04d8754419","status":"active","text":"Ba2+ resides at a single location within the selectivity filter of the KcsA K+ channel.","confidence":0.98,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/claims/cl_348c77aa6bedafc923350f04d8754419"},{"public_id":"cl_d21adf4aca766622056568287bf73ff7","status":"active","text":"The Ba2+ blocking site is on the internal aspect adjacent to the central cavity at the 'inner ion' position.","confidence":0.96,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/claims/cl_d21adf4aca766622056568287bf73ff7"},{"public_id":"cl_b9d27beb4e4b87f24cdab5a20e8f286e","status":"active","text":"The Ba2+ location in the pore agrees with prior functional findings on Ba2+ interaction with K+ and Rb+ in Ca2+-activated K+ channels.","confidence":0.89,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous 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