Structural basis of Na + -independent and cooperative substrate/product antiport in CaiT
Transport of solutes across biological membranes is performed by specialized secondary transport proteins in the lipid bilayer, and is essential for life. Here we report the structures of the sodium-independent carnitine/butyrobetaine antiporter CaiT from Proteus mirabilis (PmCaiT) at 2.3-Å and from...
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| Veröffentlicht in: | Nature (London) 2010-09, Vol.467 (7312), p.233-236 |
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| description | Transport of solutes across biological membranes is performed by specialized secondary transport proteins in the lipid bilayer, and is essential for life. Here we report the structures of the sodium-independent carnitine/butyrobetaine antiporter CaiT from Proteus mirabilis (PmCaiT) at 2.3-Å and from Escherichia coli (EcCaiT) at 3.5-Å resolution. CaiT belongs to the family of betaine/carnitine/choline transporters (BCCT), which are mostly Na+ or H+ dependent, whereas EcCaiT is Na+ and H+ independent. The three-dimensional architecture of CaiT resembles that of the Na+-dependent transporters LeuT and BetP, but in CaiT a methionine sulphur takes the place of the Na+ ion to coordinate the substrate in the central transport site, accounting for Na+-independent transport. Both CaiT structures show the fully open, inward-facing conformation, and thus complete the set of functional states that describe the alternating access mechanism. EcCaiT contains two bound butyrobetaine substrate molecules, one in the central transport site, the other in an extracellular binding pocket. In the structure of PmCaiT, a tryptophan side chain occupies the transport site, and access to the extracellular site is blocked. Binding of both substrates to CaiT reconstituted into proteoliposomes is cooperative, with Hill coefficients up to 1.7, indicating that the extracellular site is regulatory. We propose a mechanism whereby the occupied regulatory site increases the binding affinity of the transport site and initiates substrate translocation. |
| doi_str_mv | 10.1038/nature09310 |
| format | Article |
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Here we report the structures of the sodium-independent carnitine/butyrobetaine antiporter CaiT from Proteus mirabilis (PmCaiT) at 2.3-Å and from Escherichia coli (EcCaiT) at 3.5-Å resolution. CaiT belongs to the family of betaine/carnitine/choline transporters (BCCT), which are mostly Na+ or H+ dependent, whereas EcCaiT is Na+ and H+ independent. The three-dimensional architecture of CaiT resembles that of the Na+-dependent transporters LeuT and BetP, but in CaiT a methionine sulphur takes the place of the Na+ ion to coordinate the substrate in the central transport site, accounting for Na+-independent transport. Both CaiT structures show the fully open, inward-facing conformation, and thus complete the set of functional states that describe the alternating access mechanism. EcCaiT contains two bound butyrobetaine substrate molecules, one in the central transport site, the other in an extracellular binding pocket. In the structure of PmCaiT, a tryptophan side chain occupies the transport site, and access to the extracellular site is blocked. Binding of both substrates to CaiT reconstituted into proteoliposomes is cooperative, with Hill coefficients up to 1.7, indicating that the extracellular site is regulatory. We propose a mechanism whereby the occupied regulatory site increases the binding affinity of the transport site and initiates substrate translocation.</description><identifier>ISSN: 0028-0836</identifier><identifier>EISSN: 1476-4687</identifier><identifier>DOI: 10.1038/nature09310</identifier><identifier>PMID: 20829798</identifier><identifier>CODEN: NATUAS</identifier><language>eng</language><publisher>London: Nature Publishing Group UK</publisher><subject>631/337 ; 631/45/535 ; 631/57/2270/1140 ; Antiporters - chemistry ; Antiporters - metabolism ; Bacterial Proteins - chemistry ; Bacterial Proteins - metabolism ; Betaine - analogs & derivatives ; Betaine - metabolism ; Biochemistry ; Biological and medical sciences ; Biological membranes ; Biological Transport ; Carnitine - metabolism ; Crystalline structure ; E coli ; Enzymes ; Escherichia coli - metabolism ; Escherichia coli Proteins - chemistry ; Escherichia coli Proteins - metabolism ; Fundamental and applied biological sciences. Psychology ; Humanities and Social Sciences ; Hydrogen bonds ; letter ; Models, Molecular ; Molecular biophysics ; multidisciplinary ; Mutation ; Proteins ; Proteus mirabilis - metabolism ; Science ; Science (multidisciplinary) ; Solutes ; Structure in molecular biology ; Substrates ; Translocation</subject><ispartof>Nature (London), 2010-09, Vol.467 (7312), p.233-236</ispartof><rights>Springer Nature Limited 2010</rights><rights>2015 INIST-CNRS</rights><rights>Copyright Nature Publishing Group Sep 9, 2010</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c445t-873336b0c8c63659becd55157c81dab640e6b44a71718066530fce92ed772cfd3</citedby><cites>FETCH-LOGICAL-c445t-873336b0c8c63659becd55157c81dab640e6b44a71718066530fce92ed772cfd3</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://link.springer.com/content/pdf/10.1038/nature09310$$EPDF$$P50$$Gspringer$$H</linktopdf><linktohtml>$$Uhttps://link.springer.com/10.1038/nature09310$$EHTML$$P50$$Gspringer$$H</linktohtml><link.rule.ids>314,778,782,27911,27912,41475,42544,51306</link.rule.ids><backlink>$$Uhttp://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=23182560$$DView record in Pascal Francis$$Hfree_for_read</backlink><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/20829798$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Kühlbrandt, Werner</creatorcontrib><creatorcontrib>Schulze, Sabrina</creatorcontrib><creatorcontrib>Köster, Stefan</creatorcontrib><creatorcontrib>Geldmacher, Ulrike</creatorcontrib><creatorcontrib>Terwisscha van Scheltinga, Anke C</creatorcontrib><title>Structural basis of Na + -independent and cooperative substrate/product antiport in CaiT</title><title>Nature (London)</title><addtitle>Nature</addtitle><addtitle>Nature</addtitle><description>Transport of solutes across biological membranes is performed by specialized secondary transport proteins in the lipid bilayer, and is essential for life. Here we report the structures of the sodium-independent carnitine/butyrobetaine antiporter CaiT from Proteus mirabilis (PmCaiT) at 2.3-Å and from Escherichia coli (EcCaiT) at 3.5-Å resolution. CaiT belongs to the family of betaine/carnitine/choline transporters (BCCT), which are mostly Na+ or H+ dependent, whereas EcCaiT is Na+ and H+ independent. The three-dimensional architecture of CaiT resembles that of the Na+-dependent transporters LeuT and BetP, but in CaiT a methionine sulphur takes the place of the Na+ ion to coordinate the substrate in the central transport site, accounting for Na+-independent transport. Both CaiT structures show the fully open, inward-facing conformation, and thus complete the set of functional states that describe the alternating access mechanism. EcCaiT contains two bound butyrobetaine substrate molecules, one in the central transport site, the other in an extracellular binding pocket. 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Psychology</subject><subject>Humanities and Social Sciences</subject><subject>Hydrogen bonds</subject><subject>letter</subject><subject>Models, Molecular</subject><subject>Molecular biophysics</subject><subject>multidisciplinary</subject><subject>Mutation</subject><subject>Proteins</subject><subject>Proteus mirabilis - metabolism</subject><subject>Science</subject><subject>Science (multidisciplinary)</subject><subject>Solutes</subject><subject>Structure in molecular biology</subject><subject>Substrates</subject><subject>Translocation</subject><issn>0028-0836</issn><issn>1476-4687</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2010</creationdate><recordtype>article</recordtype><sourceid>EIF</sourceid><sourceid>8G5</sourceid><sourceid>ABUWG</sourceid><sourceid>AFKRA</sourceid><sourceid>AZQEC</sourceid><sourceid>BEC</sourceid><sourceid>BENPR</sourceid><sourceid>CCPQU</sourceid><sourceid>DWQXO</sourceid><sourceid>GNUQQ</sourceid><sourceid>GUQSH</sourceid><sourceid>M2O</sourceid><recordid>eNpt0E1rFTEUBuAglvZau3IvURAXddqTyecs5aJWKLqwBXdDJnNGUuZmxiQj9N-bMte2FDdJSB7evBxCXjE4Y8DNebB5iQgNZ_CMbJjQqhLK6OdkA1CbCgxXR-RFSjcAIJkWh-SoBlM3ujEb8vNHjosrAXaknU0-0Wmg3yw9pZUPPc5YlpCpDT110zRjtNn_QZqWLuVyxvM5Tn0JKCL7eYqZ-kC31l-9JAeDHROe7Pdjcv3509X2orr8_uXr9uNl5YSQuTKac646cMYprmTToeulZFI7w3rbKQGoOiGsZpoZUEpyGBw2NfZa127o-TF5v-aWIr8XTLnd-eRwHG3AaUmtlgI4AGNFvn0ib6YlhlKuICY5E4IXdLoiF6eUIg7tHP3OxtuWQXs37vbRuIt-vY9cuh329_bffAt4twc2OTsO0Qbn04PjzNRS3QV9WF0qT-EXxodu___3zcrXy_u8x-YvZryiuQ</recordid><startdate>20100909</startdate><enddate>20100909</enddate><creator>Kühlbrandt, Werner</creator><creator>Schulze, Sabrina</creator><creator>Köster, Stefan</creator><creator>Geldmacher, Ulrike</creator><creator>Terwisscha van Scheltinga, Anke C</creator><general>Nature Publishing Group UK</general><general>Nature Publishing Group</general><scope>IQODW</scope><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>3V.</scope><scope>7QG</scope><scope>7QL</scope><scope>7QP</scope><scope>7QR</scope><scope>7RV</scope><scope>7SN</scope><scope>7SS</scope><scope>7ST</scope><scope>7T5</scope><scope>7TG</scope><scope>7TK</scope><scope>7TM</scope><scope>7TO</scope><scope>7U9</scope><scope>7X2</scope><scope>7X7</scope><scope>7XB</scope><scope>88A</scope><scope>88E</scope><scope>88G</scope><scope>88I</scope><scope>8AF</scope><scope>8AO</scope><scope>8C1</scope><scope>8FD</scope><scope>8FE</scope><scope>8FG</scope><scope>8FH</scope><scope>8FI</scope><scope>8FJ</scope><scope>8FK</scope><scope>8G5</scope><scope>ABJCF</scope><scope>ABUWG</scope><scope>AEUYN</scope><scope>AFKRA</scope><scope>ARAPS</scope><scope>ATCPS</scope><scope>AZQEC</scope><scope>BBNVY</scope><scope>BEC</scope><scope>BENPR</scope><scope>BGLVJ</scope><scope>BHPHI</scope><scope>BKSAR</scope><scope>C1K</scope><scope>CCPQU</scope><scope>D1I</scope><scope>DWQXO</scope><scope>FR3</scope><scope>FYUFA</scope><scope>GHDGH</scope><scope>GNUQQ</scope><scope>GUQSH</scope><scope>H94</scope><scope>HCIFZ</scope><scope>K9.</scope><scope>KB.</scope><scope>KB0</scope><scope>KL.</scope><scope>L6V</scope><scope>LK8</scope><scope>M0K</scope><scope>M0S</scope><scope>M1P</scope><scope>M2M</scope><scope>M2O</scope><scope>M2P</scope><scope>M7N</scope><scope>M7P</scope><scope>M7S</scope><scope>MBDVC</scope><scope>NAPCQ</scope><scope>P5Z</scope><scope>P62</scope><scope>P64</scope><scope>PATMY</scope><scope>PCBAR</scope><scope>PDBOC</scope><scope>PQEST</scope><scope>PQQKQ</scope><scope>PQUKI</scope><scope>PSYQQ</scope><scope>PTHSS</scope><scope>PYCSY</scope><scope>Q9U</scope><scope>R05</scope><scope>RC3</scope><scope>S0X</scope><scope>SOI</scope><scope>7X8</scope></search><sort><creationdate>20100909</creationdate><title>Structural basis of Na + -independent and cooperative substrate/product antiport in CaiT</title><author>Kühlbrandt, Werner ; 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Academic</collection><jtitle>Nature (London)</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Kühlbrandt, Werner</au><au>Schulze, Sabrina</au><au>Köster, Stefan</au><au>Geldmacher, Ulrike</au><au>Terwisscha van Scheltinga, Anke C</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Structural basis of Na + -independent and cooperative substrate/product antiport in CaiT</atitle><jtitle>Nature (London)</jtitle><stitle>Nature</stitle><addtitle>Nature</addtitle><date>2010-09-09</date><risdate>2010</risdate><volume>467</volume><issue>7312</issue><spage>233</spage><epage>236</epage><pages>233-236</pages><issn>0028-0836</issn><eissn>1476-4687</eissn><coden>NATUAS</coden><abstract>Transport of solutes across biological membranes is performed by specialized secondary transport proteins in the lipid bilayer, and is essential for life. Here we report the structures of the sodium-independent carnitine/butyrobetaine antiporter CaiT from Proteus mirabilis (PmCaiT) at 2.3-Å and from Escherichia coli (EcCaiT) at 3.5-Å resolution. CaiT belongs to the family of betaine/carnitine/choline transporters (BCCT), which are mostly Na+ or H+ dependent, whereas EcCaiT is Na+ and H+ independent. The three-dimensional architecture of CaiT resembles that of the Na+-dependent transporters LeuT and BetP, but in CaiT a methionine sulphur takes the place of the Na+ ion to coordinate the substrate in the central transport site, accounting for Na+-independent transport. Both CaiT structures show the fully open, inward-facing conformation, and thus complete the set of functional states that describe the alternating access mechanism. EcCaiT contains two bound butyrobetaine substrate molecules, one in the central transport site, the other in an extracellular binding pocket. In the structure of PmCaiT, a tryptophan side chain occupies the transport site, and access to the extracellular site is blocked. Binding of both substrates to CaiT reconstituted into proteoliposomes is cooperative, with Hill coefficients up to 1.7, indicating that the extracellular site is regulatory. We propose a mechanism whereby the occupied regulatory site increases the binding affinity of the transport site and initiates substrate translocation.</abstract><cop>London</cop><pub>Nature Publishing Group UK</pub><pmid>20829798</pmid><doi>10.1038/nature09310</doi><tpages>4</tpages><oa>free_for_read</oa></addata></record> |
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| subjects | 631/337 631/45/535 631/57/2270/1140 Antiporters - chemistry Antiporters - metabolism Bacterial Proteins - chemistry Bacterial Proteins - metabolism Betaine - analogs & derivatives Betaine - metabolism Biochemistry Biological and medical sciences Biological membranes Biological Transport Carnitine - metabolism Crystalline structure E coli Enzymes Escherichia coli - metabolism Escherichia coli Proteins - chemistry Escherichia coli Proteins - metabolism Fundamental and applied biological sciences. Psychology Humanities and Social Sciences Hydrogen bonds letter Models, Molecular Molecular biophysics multidisciplinary Mutation Proteins Proteus mirabilis - metabolism Science Science (multidisciplinary) Solutes Structure in molecular biology Substrates Translocation |
| title | Structural basis of Na + -independent and cooperative substrate/product antiport in CaiT |
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