title: Conformational changes required for H(+)/Cl(-) exchange mediated by a CLC transporter.
abstract: CLC-type exchangers mediate transmembrane Cl(-) transport. Mutations altering their gating properties cause numerous genetic disorders. However, their transport mechanism remains poorly understood. In conventional models, two gates alternatively expose substrates to the intra- or extracellular solutions. A glutamate was identified as the only gate in the CLCs, suggesting that CLCs function by a nonconventional mechanism. Here we show that transport in CLC-ec1, a prokaryotic homolog, is inhibited by cross-links constraining movement of helix O far from the transport pathway. Cross-linked CLC-ec1 adopts a wild-type-like structure, indicating stabilization of a native conformation. Movements of helix O are transduced to the ion pathway via a direct contact between its C terminus and a tyrosine that is a constitutive element of the second gate of CLC transporters. Therefore, the CLC exchangers have two gates that are coupled through conformational rearrangements outside the ion pathway.
authors.affiliation: Department of Anesthesiology, Weill Cornell Medical College, New York, New York, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Basilio
authors.affiliation: Department of Anesthesiology, Weill Cornell Medical College, New York, New York, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Noack
authors.affiliation: Department of Anesthesiology, Weill Cornell Medical College, New York, New York, USA.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Picollo
authors.affiliation: 1] Department of Anesthesiology, Weill Cornell Medical College, New York, New York, USA. [2] Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York, USA. [3] Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA.
authors.forename: Alessio
authors.initials: A
authors.lastname: Accardi
mesh_terms: D001692:Biological Transport / Q000502:physiology; D018118:Chloride Channels / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D018360:Crystallography, X-Ray; D048168:Escherichia coli K12 / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D008958:Models, Molecular; D009154:Mutation; D017434:Protein Structure, Tertiary
chemical_list: D018118:Chloride Channels; D029968:Escherichia coli Proteins
references.citation: Nature. 2008 Jun 5;453(7196):788-92
references.pmid: 18449189
references.citation: J Gen Physiol. 2003 Nov;122(5):641-51
references.pmid: 14581587
references.citation: Nat Struct Mol Biol. 2008 Aug;15(8):805-10
references.pmid: 18641661
references.citation: Crit Rev Biochem Mol Biol. 2008 Jan-Feb;43(1):3-36
references.pmid: 18307107
references.citation: J Gen Physiol. 2004 Feb;123(2):109-19
references.pmid: 14718478
references.citation: J Gen Physiol. 2007 Oct;130(4):335-49
references.pmid: 17846164
references.citation: J Membr Biol. 2011 Jan;239(1-2):85-93
references.pmid: 21161516
references.citation: Nature. 2012 Jan 09;481(7382):469-74
references.pmid: 22230955
references.citation: Proc Natl Acad Sci U S A. 2007 Dec 26;104(52):20659-65
references.pmid: 18093952
references.citation: Nature. 2010 Dec 9;468(7325):844-7
references.pmid: 21048711
references.citation: J Physiol. 2004 Mar 16;555(Pt 3):671-82
references.pmid: 14724195
references.citation: Nature. 2012 Oct 4;490(7418):126-30
references.pmid: 22940865
references.citation: Nature. 2002 Oct 17;419(6908):715-8
references.pmid: 12384697
references.citation: J Gen Physiol. 2003 Sep;122(3):277-93
references.pmid: 12913090
references.citation: Nat Struct Mol Biol. 2009 Dec;16(12):1294-301
references.pmid: 19898476
references.citation: Biophys J. 2008 Nov 15;95(10):4668-75
references.pmid: 18658230
references.citation: EMBO J. 2009 Oct 21;28(20):3090-102
references.pmid: 19745816
references.citation: Nat Commun. 2013;4:2507
references.pmid: 24064982
references.citation: J Gen Physiol. 1999 Mar;113(3):457-68
references.pmid: 10051520
references.citation: J Biol Chem. 2009 Sep 25;284(39):26526-32
references.pmid: 19636075
references.citation: Nature. 2006 Aug 24;442(7105):939-42
references.pmid: 16878138
references.citation: Proc Natl Acad Sci U S A. 2012 Sep 18;109(38):15289-94
references.pmid: 22949689
references.citation: EMBO J. 2006 Jan 11;25(1):24-33
references.pmid: 16341087
references.citation: Nature. 2009 Dec 17;462(7275):880-5
references.pmid: 19924125
references.citation: Hum Mol Genet. 1997 May;6(5):805-11
references.pmid: 9158157
references.citation: J Gen Physiol. 2007 Apr;129(4):317-29
references.pmid: 17389248
references.citation: Nature. 2002 Jan 17;415(6869):287-94
references.pmid: 11796999
references.citation: J Gen Physiol. 2003 Sep;122(3):295-306
references.pmid: 12913089
references.citation: Annu Rev Biophys. 2013;42:51-72
references.pmid: 23654302
references.citation: Biochemistry. 2006 Jun 6;45(22):6773-82
references.pmid: 16734414
references.citation: Nature. 2004 Feb 26;427(6977):803-7
references.pmid: 14985752
references.citation: J Gen Physiol. 2005 Dec;126(6):563-70
references.pmid: 16316975
references.citation: Science. 2003 Apr 4;300(5616):108-12
references.pmid: 12649487
references.citation: Neuron. 1995 Dec;15(6):1455-63
references.pmid: 8845168
references.citation: Biochim Biophys Acta. 2011 Feb;1807(2):167-88
references.pmid: 21029721
references.citation: Nature. 2007 Dec 13;450(7172):1043-9
references.pmid: 18075585
references.citation: Biochim Biophys Acta. 2010 Aug;1798(8):1457-64
references.pmid: 20188062
references.citation: J Physiol. 1997 Feb 1;498 ( Pt 3):691-702
references.pmid: 9051580
references.citation: Acta Crystallogr D Biol Crystallogr. 2010 Feb;66(Pt 2):213-21
references.pmid: 20124702
references.citation: J Mol Biol. 2006 Sep 29;362(4):682-90
references.pmid: 16905147
references.citation: Nature. 2007 Dec 13;450(7172):1036-42
references.pmid: 18075584
references.citation: Biochemistry. 2011 Feb 8;50(5):788-94
references.pmid: 21174448
references.citation: J Biol Chem. 2008 Feb 15;283(7):4219-27
references.pmid: 18063579
references.citation: Proc Natl Acad Sci U S A. 2012 Jul 17;109(29):11699-704
references.pmid: 22753511
references.citation: J Gen Physiol. 1997 Aug;110(2):165-71
references.pmid: 9236209
references.citation: J Gen Physiol. 1999 Nov;114(5):713-22
references.pmid: 10539975
references.citation: Nature. 1966 Aug 27;211(5052):969-70
references.pmid: 5968307
references.citation: EMBO Rep. 2009 Oct;10(10):1111-6
references.pmid: 19713962
references.citation: Nature. 2005 Jul 21;436(7049):420-3
references.pmid: 16034421
references.citation: Proc Natl Acad Sci U S A. 2008 Aug 12;105(32):11194-9
references.pmid: 18678918
references.citation: Nat Struct Mol Biol. 2012 Apr 08;19(5):525-31, S1
references.pmid: 22484316
references.citation: Biophys J. 2011 Mar 2;100(5):1233-41
references.pmid: 21354396
references.citation: J Appl Crystallogr. 2007 Aug 1;40(Pt 4):658-674
references.pmid: 19461840
references.citation: Nature. 2005 Jul 21;436(7049):424-7
references.pmid: 16034422
references.citation: Proc Natl Acad Sci U S A. 2003 Jan 21;100(2):501-5
references.pmid: 12518045
references.citation: Nat Struct Mol Biol. 2006 Dec;13(12):1115-9
references.pmid: 17115052
references.citation: EMBO J. 2011 Jun 1;30(11):2140-52
references.pmid: 21527911
references.citation: Hum Mutat. 2002 Apr;19(4):423-34
references.pmid: 11933197
references.citation: J Mol Biol. 2006 Sep 29;362(4):691-9
references.pmid: 16949616
references.citation: Science. 2010 Oct 29;330(6004):635-41
references.pmid: 20929736