2.A.49.2.11 The voltage-gated torpedo chloride channel, CLC-0, of 810 aas. This
channel is thought to ensure the high conductance of the non-innervated
membrane of the electrocyte necessary for efficient current generation
caused by sodium influx through the acetylcholine receptor at the
innervated membrane. ClC-0 is a homodimer with
separate pores in each subunit. Each protopore can be opened and closed independently from the other
pore by a ""fast gate"". A common, slow gate acts on both pores simultaneously. The opening of the
fast gate is controlled by a critical glutamate (E166), whose protonation state determines the fast
gate's pH dependence (Zifarelli and Pusch 2010). Extracellular protons likely arrive directly at E166, but
protonation of E166 from the inside may be mediated by the dissociation of an
intrapore water molecule. The OH- anion resulting from dissociation of water is stabilized in one
of the anion binding sites of the channel, competing with intracellular Cl-. Proton translocation
drives irreversible gating transitions associated with the slow gate (Zifarelli and Pusch 2010). The structure of the cytoplasmic domain has been solved (Meyer and Dutzler 2006). It contains a folded core of two tightly interacting cystathionine beta-synthetase (CBS) subdomains which are connected by a 96 residue mobile linker. The domains form dimers, thereby extending the 2-fold symmetry of the transmembrane pore.
|
Accession Number: | P35522 |
Protein Name: | Chloride channel protein |
Length: | 810 |
Molecular Weight: | 89447.00 |
Species: | Torpedo californica (Pacific electric ray) [7787] |
Number of TMSs: | 11 |
Location1 / Topology2 / Orientation3: |
Membrane1 / Multi-pass membrane protein2 |
Substrate |
chloride |
---|
1: MSHEKNEASG NPEAQSWKAQ EAMLGVKTEV SRWRAVKNCL YRHLVKVLGE DWIFLLLLGA
61: LMALVSWAMD FIGSRGLRFY KYLFAMVEGN LGLQYLVWVC YPLILILFSS LFCQIVSPQA
121: VGSGIPELKT IIRGAVLHEY LTLRTFVAKT VGLTVALSAG FPLGKEGPFV HIASICATLL
181: NQLLCFISGR REEPYYLRAD ILTVGCALGI SCCFGTPLAG VLFSIEVTCS HFGVRSYWRG
241: FLGGAFSAFI FRVLSVWVKD TVTLTALFKT NFRGDIPFDL QELPAFAIIG IASGFFGALF
301: VYLNRQIIVF MRKKNFVTKI LKKQRLIYPA VVTFVLATLR FPPGVGQFFG AGLMPRETIN
361: SLFDNYTWTK TIDPRGLGNS AQWFIPHLNI FIVMALYFVM HFWMAALAVT MPVPCGAFVP
421: VFNLGAVLGR FVGELMALLF PDGLVSNGNL YHILPGEYAV IGAAAMTGAV THAVSTAVIC
481: FELTGQISHV LPMMVAVILA NMVAQGLQPS LYDSIIQIKK LPYLPELSWS SANKYNIQVG
541: DIMVRDVTSI ASTSTYGDLL HVLRQTKLKF FPFVDTPETN TLLGSIERTE VEGLLQRRIS
601: AYRRQPATAA EAEEEGRNGE RGASFTGDVP GEAETSFAYI DQEEAEGQQQ REGLEAVKVQ
661: TEDPRPPSPV PAEEPTQTSG IYQKKHKGTG QVASRFEEML TLEEIYQWEQ REKNVVVNFE
721: TCRIDQSPFQ LVEGTSLQKT HTLFSLLGLD RAYVTSMGKL VGVVALAEIQ AAIEGSYQKG
781: FRLPPPLASF RDAKNARNSG RTATSNSSGK