Ion channel structure: Emerging structure of the Nicotinic Acetylcholine receptors

Nature Reviews Neuroscience

Volumn 3, Issue 2, 2002, Pages 102-114

  Karlin, Arthur ^a  

^a Och Spine at New York Presbyterian Hospitals   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ACETYLCHOLINE; ACHBP PROTEIN, LYMNAEA; CARRIER PROTEIN; ION CHANNEL; LIGAND; NICOTINIC RECEPTOR;

ANIMAL; BINDING SITE; CELL MEMBRANE; HUMAN; METABOLISM; PHYSIOLOGY; PROTEIN TERTIARY STRUCTURE; REVIEW; SYNAPTIC TRANSMISSION;

ACETYLCHOLINE; ANIMALS; BINDING SITES; CARRIER PROTEINS; CELL MEMBRANE; HUMANS; ION CHANNELS; LIGANDS; PROTEIN STRUCTURE, TERTIARY; RECEPTORS, NICOTINIC; SYNAPTIC TRANSMISSION;

EID: 0036480194     PISSN: 1471003X     EISSN: 14710048     Source Type: Journal    
DOI: 10.1038/nrn731     Document Type: Article

References (168)

1. Langley, J. N. On the contraction of muscle chiefly in relation to the presence of receptive substances. Part 1. J. Physiol. (Lond.) 36, 347-384 (1907).
2. Katz, B. & Thesleff, S. A study of 'desensitization' produced by acetylcholine at the motor end-plate. J. Physiol. (Lond) 138, 63-80 (1957).
3. Kao, P N. & Karlin, A. Acetylcholine receptor binding site contains a disulfide cross-link between adjacent half-cystinyl residues. J. Biol. Chem. 261, 8085-8088 (1986).
4. Karlin, A. & Akabas, M. H. Toward a structural basis for the function of nicotinic acetylcholine receptors and their cousins. Neuron 15, 1231-1244 (1995).
5. Ortells, M. O. & Lunt, G. G. Evolutionary history of the ligand-gated ion-channel superfamily of receptors. Trends Neurosci. 18, 121-127 (1995).
6. Tsunoyama, K. & Gojobori, T. Evolution of nicotinic acetylcholine receptor subunits. Mol. Biol. Evol. 15, 518-527 (1998).
7. Cully, D. F. et al. Cloning an avermectin-sensitive glutamate- gated chloride channel from Caenorhabditis elegans. Nature 371, 707-711 (1994).
8. Zheng, Y. et al. Identification of two novel Drosophila melanogasterhistamine-gated chloride channel subunits expressed in the eye. J. Biol. Chem. 277, 2000-2005 (2002).
9. Reynolds, J. A. & Karlin, A. Molecular weight in detergent solution of acetylcholine receptor from Torpedo californica. Biochemistry 17, 2035-2038 (1978).
10. Mishina, M. et al. Molecular distinction between fetal and adult forms of muscle acetylcholine receptor. Nature 321, 406-411 (1986).
11. Anand, R., Conroy, W. G., Schoepfer, R., Whiting, P. & Lindstrom, J. Neuronal nicotinic acetylcholine receptors expressed in Xenopus oocytes have a pentameric quaternary structure. J. Biol. Chem. 266, 11192-11198 (1991).
12. Cooper, E., Couturier, S. & Ballivet, M. Pentameric structure and subunit stoichiometry of a neuronal nicotinic acetylcholine receptor. Nature 350, 235-238 (1991).
13. Elgoyhen, A. B., Johnson, D. S., Boulter, J., Vetter, D. E. & Heinemann, S.α9: an acetylcholine receptor with novel pharmacological properties expressed in rat cochlear hair cells. Cell 79, 705-715 (1994).
14. Gotti, C. et al. Pharmacology and biophysical properties of α7 and α7- α8 α-bungarotoxin receptor subtypes immunopurified from the chick optic lobe. Eur. J. Neurosci. 6, 1281-1291 (1994).
15. Vernallis, A. B., Conroy, W. G. & Berg, D. K. Neurons assemble acetylcholine receptors with as many as three kinds of subunits while maintaining subunit segregation among receptor subtypes. Neuron 10, 451-464 (1993).
16. Le Novere, N., Zoli, M. & Changeux, J. P Neuronal nicotinic receptor α6 subunit mRNA is selectively concentrated in catecholaminergic nuclei of the rat brain. Eur. J. Neurosci. 8, 2428-2439 (1996).
17. Ramirez-Latorre, J. et al. Functional contributions of α5 subunit to neuronal acetylcholine receptor channels. Nature 380, 347-351 (1996).
18. Elgoyhen, A. B. et al. α10: a determinant of nicotinic cholinergic receptor function in mammalian vestibular and cochlear mechanosensory hair cells. Proc. Natl Acad. Sci. USA 98, 3501-3506 (2001).
19. Karlin, A. et al. The arrangement of the subunits of the acetylcholine receptor of Torpedo californica. J. Biol. Chem. 258, 6678-6681 (1983).
20. Stroud, R. M., McCarthy, M. P. & Shuster, M. Nicotinic acetylcholine receptor superfamily of ligand-gated ion channels. Biochemistry 29, 11009-11023 (1990).
21. Unwin, N. Nicotinic acetylcholine receptor at 9 A resolution. J. Mol. Biol. 229, 1101-1124 (1993).
22. Miyazawa, A., Fujiyoshi, Y., Stowell, M. & Unwin, N. Nicotinic acetylcholine receptor at 4.6 Å resolution: transverse tunnels in the channel wall. J. Mol. Biol. 288, 765-786 (1999).
23. Sakmann, B., Patlak, J. & Neher, E. Single acetylcholine- activated channels show burst-kinetics in presence of desensitizing concentrations of agonist. Nature 286, 71-73 (1981).
24. Neubig, R. R., Boyd, N. D. & Cohen, J. B. Conformations of Torpedo acetylcholine receptor associated with ion transport and desensitization. Biochemistry 21, 3460-3467 (1982).
25. Heidmann, T., Bernhardt, J., Neumann, E. & Changeux, J. P. Rapid kinetics of agonist-binding and permeability response analyzed in parallel on acetylcholine receptor rich membranes from Torpedo marmorata. Biochemistry 22, 5452-5459 (1983).
26. Jackson, M. B. Perfection of a synaptic receptor: kinetics and energetics of the acetylcholine receptor. Proc. Natl Acad. Sci. USA 86, 2199-2203 (1989).
27. Auerbach, A. A statistical analysis of acetylcholine receptor activation inXenopus myocytes: stepwise versus concerted models of gating. J. Physiol. (Lond.) 461, 339-378 (1993).
28. Hess, G. Determination of the chemical mechanism of neurotransmitter receptor-mediated reaction by rapid chemical kinetic techniques. Biochemistry 32, 989-1000 (1993).
29. Edelstein, S. J., Schaad, O., Henry, E., Bertrand, D. & Changeux, J. P. A kinetic mechanism for nicotinic acetylcholine receptors based on multiple allosteric transitions. Biol. Cybern. 75, 361-379 (1996).
30. Auerbach, A. & Akk, G. Desensitization of mouse nicotinic acetylcholine receptor channels. A two-gate mechanism. J. Gen. Physiol. 112, 181-197 (1998).
31. Prince, R. J. & Sine, S. M. Acetylcholine and epibatidine binding to muscle acetylcholine receptors distinguish between concerted and uncoupled models. J. Biol. Chem. 274, 19623-19629 (1999).
32. Reitstetter, R., Lukas, R. J. & Gruener, R. Dependence of nicotinic acetylcholine receptor recovery from desensitization on the duration of agonist exposure. J. Pharmacol. Exp. Ther. 289, 656-660 (1999).
33. Grosman, C. & Auerbach, A. The dissociation of acetylcholine from open nicotinic receptor channels. Proc. Natl Acad. Sci. USA 98, 14102-14107 (2001).
34. Jones, M. V. & Westbrook, G. L. The impact of receptor desensitization on fast synaptic transmission. Trends Neurosci. 19, 96-101 (1996).
35. Monod, J., Wyman, J. & Changeux, J.-P. On the nature of allosteric transitions: a plausible model. J. Mol. Biol. 12, 88-118 (1965).
36. Changeux, J.-P, Thiery J., Tung, Y & Kittel, C. On the cooperativity of biological membranes. Proc. Natl Acad. Sci. USA 57, 335-341 (1967).
37. Karlin, A. On the application of 'a plausible model' of allosteric proteins to the receptor for acetylcholine. J. Theor. Biol. 16, 306-320 (1967).
38. Kawai, H., Cao, L., Dunn, S. M., Dryden, W. F. & Raftery, M. A. Interaction of a semirigid agonist with Torpedo acetylcholine receptor. Biochemistry 39, 3867-3876 (2000).
39. Krauss, M., Korr, D., Herrmann, A. & Hucho, F. Binding properties of agonists and antagonists to distinct allosteric states of the nicotinic acetylcholine receptor are incompatible with a concerted model. J. Biol. Chem. 275, 30196-30201 (2000).
40. Brqc, K. et al. Crystal structure of an ACh-binding protein reveals the ligand-binding domain of nicotinic receptors. Nature 411, 269-276 (2001).
41. Smit, A. B. et al. A glia-derived acetylcholine-binding protein that modulates synaptic transmission. Nature 411, 261-268 (2001).
42. Ratnam, M. et al. Location of antigenic determinants on primary sequences of subunits of nicotinic acetylcholine receptor by peptide mapping. Biochemistry 25, 2621-2632 (1986).
43. Le Novere, N., Corringer, P. J. & Changeux, J. P. Improved secondary structure predictions for a nicotinic receptor subunit: incorporation of solvent accessibility and experimental data into a two-dimensional representation. Biophys. J. 76, 2329-2345 (1999)
44. Karlin, A. Explorations of the nicotinic acetylcholine receptor. Harvey Led. 85, 71-107 (1991).
45. Reiter, M. J., Cowburn, D. A., Prives, J. M. & Karlin, A. Affinity labeling of the acetylcholine receptor in the electroplax: electrophoretic separation in sodium dodecyl sulfate. Proc. NatlAcad. Sci. USA 69, 1168-1172 (1972).
46. Kao, P. N. et al. Identification of the α subunit half-cystine specifically labeled by an affinity reagent for the acetylcholine receptor binding site. J. Biol. Chem. 259, 11662-11665 (1984).
47. Galzi, J.-L. et al. Identification of a novel amino acid α- tyrosine 93 within the cholinergic ligand-binding sites of the acetylcholine receptor by photolabeling. Additional evidence for a three-loop model of the cholinergic ligand-binding site. J. Biol. Chem. 265, 10430-10437 (1990).
48. Cohen, B. N., Labarca, C., Davidson, N. & Lester, H. A. Mutations in M2 alter the selectivity of the mouse nicotinic acetylcholine receptor for organic and alkali metal cations. J. Gen. Physiol. 100, 373-400 (1992).
49. Kurosaki, T. et al. Functional properties of nicotinic acetylcholine receptor subunits expressed in various combinations. FEBS Lett. 214, 253-258 (1987).
50. Blount, P. & Merlie, J. P Molecular basis of the two nonequivalent ligand binding sites of the muscle nicotinic acetylcholine receptor. Neuron 3, 349-357 (1989).
51. Sine, S. M. & Claudio, T γ- and δ-subunits regulate the affinity and the cooperativity of ligand binding to the acetylcholine receptor. J. Biol. Chem. 266, 19369-19377 (1991).
52. Sine, S. M. Molecular dissection of subunit interfaces in the acetylcholine receptor: identification of residues that determine curare selectivity. Proc. Natl Acad. Sci. USA 90, 9436-9440 (1993).
53. Wang, D., Chiara, D. C., Xie, Y & Cohen, J. B. Probing the structure of the nicotinic acetylcholine receptor with 4-benzoylbenzoylcholine, a novel photoaffinity competitive antagonist. J. Biol. Chem. 275, 28666-28674 (2000).
54. Czajkowski, C. & Karlin, A. Structure of the nicotinic receptor acetylcholine-binding site. Identification of acidic residues in the δ subunit within 0.9 nm of the α subunit binding site disulfide. J. Biol. Chem. 270, 3160-3164 (1995).
55. Pedersen, S. E. & Cohen, J. B. D-Tubocurarine binding sites are located at α- γ and α-δ subunit interfaces of the nicotinic acetylcholine receptor. Proc. Natl Acad. Sci. USA 87, 2785-2789 (1990).
56. Czajkowski, C. & Karlin, A. Agonist binding site of Torpedo electric tissue nicotinic acetylcholine receptor. A negatively charged region of the δ subunit within 0.9 nm of the α subunit binding site disulfide. J. Biol. Chem. 266, 22603-22612 (1991).
57. Machold, J. et al. Photolabeling reveals the proximity of the α-neurotoxin binding site to the M2 helix of the ion channel in the nicotinic acetylcholine receptor. Proc. Natl Acad. Sci. USA 92, 7282-7286 (1995).
58. Zhong, W. et al. From ab initio quantum mechanics to molecular neurobiology: a cation-π binding site in the nicotinic receptor. Proc. Natl Acad. Sci. USA 95, 12088-12093 (1998).
59. Schmitt, J. D., Sharples, C. G. & Caldwell, W. S. Molecular recognition in nicotinic acetylcholine receptors: the importance of π -cation interactions. J. Med. Chem. 42, 3066-3074 (1999).
60. Martin, M. D. & Karlin, A. Functional effects on the acetylcholine receptor of multiple mutations of γAsp174 and δ Asp180. Biochemistry 36, 10742-10750 (1997).
61. Akk, G., Zhou, M. & Auerbach, A. A mutational analysis of the acetylcholine receptor channel transmitter binding site. Biophys. J. 76, 207-218 (1999).
62. Stauffer, D. A. & Karlin, A. Electrostatic potential of the acetylcholine binding sites in the nicotinic receptor probed by reactions of binding-site cysteines with charged methanethiosulfonates. Biochemistry 33, 6840-6849 (1994).
63. Osaka, H., Sugiyama, N. & Taylor, P. Distinctions in agonist and antagonist specificity conferred by anionic residues of the nicotinic acetylcholine receptor. J. Biol. Chem. 273, 12758-12765 (1998).
64. Karlin, A. Chemical modification of the active site of the acetylcholine receptor. J. Gen. Physiol. 54, 245S-264S (1969).
65. Sullivan, D. A. & Cohen, J. B. Mapping the agonist binding site of the nicotinic acetylcholine receptor. Orientation requirements for activation by covalent agonist. J. Biol. Chem. 275, 12651-12660 (2000).
66. 3H]Acetylcholine mustard identifies residues in the cation- binding subsite. J. Biol. Chem. 266, 23354-23364 (1991).
67. Armstrong, N. & Gouaux, E. Mechanisms for activation and antagonism of an AMPA-sensitive glutamate receptor: crystal structures of the GluR2 ligand binding core. Neuron 28, 165-181 (2000).
68. Damle, V. N. & Karlin, A. Effects of agonists and antagonists on the reactivity of the binding site disulfide in acetylcholine receptor from Toledo californica. Biochemistry 19, 3924-3932 (1980).
69. Steinbach, J. H. & Chen, Q. Antagonist and partial agonist actions of D-tubocurarine at mammalian muscle acetylcholine receptors. J. Neurosci. 15, 230-240 (1995).
70. Revah, F. et al. Mutations in the channel domain alter desensitization of a neuronal nicotinic receptor. Nature 353, 846-849 (1991).
71. Mishina, M. et al. Location of functional regions of acetylcholine receptor α-subunit by site directed mutagenesis. Nature 313, 364-369 (1985).
72. Galzi, J. L. et al. Functional significance of aromatic amino acids from three peptide loops of the α7 neuronal nicotinic receptor site investigated by site-directed mutagenesis. FEBS Lett. 294, 198-202 (1991).
73. Sine, S. M., Quiram, P., Papanikolaou, F., Kreienkamp, H. J. & Taylor, P. Conserved tyrosines in the α subunit of the nicotinic acetylcholine receptor stabilize quaternary ammonium groups of agonists and curariform antagonists. J. Biol. Chem. 269, 8808-8816 (1994).
74. Tomaselli, G. F, McLaughlin, J. T., Jurman, M. E., Hawrot, E. & Yellen, G. Mutations affecting agonist sensitivity of the nicotinic acetylcholine receptor. Biophys. J. 60, 721-727 (1991).
75. O'Leary, M. E., Filatov, G. N. & White, M. M. Characterization of D-tubocurarine binding site of Torpedo acetylcholine receptor. Am. J. Physiol. 266, C648-C653 (1994).
76. Xie, Y & Cohen, J. B. Contributions of Toledo nicotinic acetylcholine receptor γ Trp-55 and δ Trp-57 to agonist and competitive antagonist function. J. Biol. Chem. 276, 2417-2426 (2001).
77. Sine, S. M., Kreienkamp, H. J., Bren, N., Maeda, R. & Taylor, P. Molecular dissection of subunit interfaces in the acetylcholine receptor: identification of determinants of α-conotoxin M1 selectivity. Neuron 15, 205-211 (1995).
78. Chiara, D. C., Xie, Y & Cohen, J. B. Structure of the agonist- binding sites of the Torpedo nicotinic acetylcholine receptor: affinity-labeling and mutational analyses identify γ Tyr-111/ δ Arg-113 as antagonist affinity determinants. Biochemistry 38, 6689-6698 (1999).
79. Sine, S. M. Identification of equivalent residues in the γ, δ, and ε subunits of the nicotinic receptor that contribute to α-bungarotoxin binding. J. Biol. Chem. 272, 23521-23527 (1997).
80. Damle, V N. & Karlin, A. Affinity labeling of one of two α-neurotoxin binding sites in acetylcholine receptor from Torpedo californica. Biochemistry 17, 2039-2045 (1978).
81. Martinez, K L., Corringer, P J., Edelstein, S. J., Changeux, J. P. & Merola, F. Structural differences in the two agonist binding sites of the Torpedo nicotinic acetylcholine receptor revealed by time-resolved fluorescence spectroscopy. Biochemistry 39, 6979-6990 (2000).
82. McArdle, J. J. et al. Waglerin-1 selectively blocks the epsilon form of the muscle nicotinic acetylcholine receptor. J. Pharmacol Exp. Ther. 289, 543-550 (1999).
83. Molles, B. E. et al. Identification of residues at the α and ε subunit interfaces mediating species selectivity of Waglerin-1 for nicotinic acetylcholine receptors. J. Biol. Chem. 27 November 2001 [epub ahead of print].
84. Osaka, H., Malany, S., Molles, B. E., Sine, S. M. & Taylor, P Pairwise electrostatic interactions between α-neurotoxins and γ, δ, and ε subunits of the nicotinic acetylcholine receptor. J. Biol. Chem. 275, 5478-5484 (2000).
85. Edelstein, S. & Changeux, J. P Allosteric transitions of the acetylcholine receptor. Adv. Protein Chem. 51, 121-184.(1998).
86. Lee, C. Y. Chemistry and pharmacology of polypeptide toxins in snake venoms. Annu. Rev. Pharmacol 12, 265-286 (1972).
87. Changeux, J. P, Kasai, M. & Lee, C. Y Use of a snake venom toxin to characterize the cholinergic receptor protein. Proc. NatlAcad. Sci. USA 67, 1241-1247 (1970).
88. Miledi, R., Molinoff, P & Potter, L. T. Isolation of the cholinergic receptor protein of Toledo electric tissue. Nature 229, 554-557 (1971).
89. Tsetlin, V. Snake venom a-neurotoxins and other 'three- finger' proteins. Eur. J. Biochem. 264, 281-286 (1999).
90. 125I-α-bungarotoxin binding activity to the α subunit of Toledo acetylcholine receptor isolated by gel electrophoresis in sodium dodecyl sulfate. J. Biol. Chem. 256, 8294-8297 (1981).
91. Wilson, P T., Lentz, T. L. & Hawrot, E. Determination of the primary amino acid sequence specifying the α-bungarotoxin binding site on the α subunit of the acetylcholine receptor from Torpedo californica. Proc. Natl Acad. Sci USA 82, 8790-8794 (1985).
92. Neumann, D., Barchan, D., Safran, A., Gershoni, J. M. & Fuchs, S. Mapping of the α -bungarotoxin binding site within the α subunit of the acetylcholine receptor. Proc. NatlAcad. Sci. USA 83, 3008-3011 (1986).
93. Samson, A. O., Chill, J. H., Rodriguez, E., Scherf, T. & Anglister, J. NMR mapping and secondary structure determination of the major acetylcholine receptor α -subunit determinant interacting with α-bungarotoxin. Biochemistry 40, 5464-5473 (2001).
94. Harel, M. et al. The binding site of acetylcholine receptor as visualized in the X-ray structure of a complex between α-bungarotoxin and a mimotope peptide. Neuron 32, 173-174 (2001).
95. Kreienkamp, H. J., Sine, S. M., Maeda, R. K. & Taylor, P. Glycosylation sites selectively interfere with α -toxin binding to the nicotinic acetylcholine receptor. J. Biol. Chem. 269, 8108-8114 (1994).
96. Antil, S., Servent, D. & Menez, A. Variability among the sites by which curaremimetic toxins bind to Toledo acetylcholine receptor, as revealed by identification of the functional residues of α-cobratoxin. J. Biol. Chem. 274, 34851-34858 (1999).
97. Spura, A. et al. Biotinylation of substituted cysteines in the nicotinic acetylcholine receptor reveals distinct binding modes for α-bungarotoxin and erabutoxin a. J. Biol. Chem. 275, 22452-22460 (2000).
98. Spura, A. et al. Probing the agonist domain of the nicotinic acetylcholine receptor by cysteine scanning mutagenesis reveals residues in proximity to the α-bungarotoxin binding site. Biochemistry 38, 4912-4921 (1999).
99. Gorne-Tschelnokow, U., Strecker, A., Kaduk, C., Naumann, D. & Hucho, F. The transmembrane domains of the nicotinic acetylcholine receptor contain α-helical and β structures. EMBO J. 13, 338-341 (1994).
100. Methot, N., Ritchie, B. D., Blanton, M. P. & Baenziger, J. E. Structure of the pore-forming transmembrane domain of a ligand-gated ion channel. J. Biol. Chem. 276, 23726-23732 (2001).
101. Akabas, M. H., Kaufmann, C., Archdeacon, P & Karlin, A. Identification of acetylcholine receptor channel-lining residues in the entire M2 segment of the α subunit. Neuron 13, 919-927 (1994).
102. Zhang, H. & Karlin, A. Contribution of the β subunit M2 segment to the ion-conducting pathway of the acetylcholine receptor. Biochemistry 37, 7952-7964 (1998).
103. Akabas, M. H. & Karlin, A. Identification of acetylcholine receptor channel-lining residues in the M1 segment of the α subunit. Biochemistry 34, 12496-12500 (1995).
104. Zhang, H. & Karlin, A. Identification of acetylcholine receptor channel-lining residues in the M1 segment of the β subunit. Biochemistry 36, 15856-15864 (1997).
105. Blanton, M. P. & Cohen, J. B. Identifying the lipid-protein interface of the Torpedo nicotinic acetylcholine receptor: secondary structure implication. Biochemistry 33, 2859-2872 (1994).
106. 3H]-diazofluorene. J. Biol. Chem. 273, 8659-8668 (1998).
107. Claudio, T, Ballivet, M., Patrick, J. & Heinemann, S. Nucleotide and deduced amino acid sequences of Torpedo californica acetylcholine receptor γ subunit. Proc. NatlAcad. Sci. USA 80, 1111-1115 (1983)
108. Devillers-Thiery, A., Giraudat, J., Bentaboulet, M. & Changeux, J.-P. Complete mRNA coding sequence of the acetylcholine binding α subunit of Toledo marmorata acetylcholine receptor: a model for the transmembrane organization of the polypeptide chain. Proc. Natl Acad. Sci. USA 80, 2067-2071 (1983).
109. Noda, M. et al. Structural homology of Toledo californica acetylcholine receptor subunits. Nature 302, 528-532 (1983).
110. Tamamizu, S. et al. Functional effects of periodic tryptophan substitutions in the α M4 transmembrane domain of the Torpedo californica nicotinic acetylcholine receptor. Biochemistry 39, 4666-4673 (2000).
111. Hille, B. Ionic Channels of Excitable Membranes (Sinauer Associates, Sunderland, Massachusetts, 1992).
112. Sakmann, B. Nobel Lecture. Elementary steps in synaptic transmission revealed by currents through single ion channels. Neuron 8, 613-629 (1992).
113. Dani, J. A. Open channel structure and ion binding sites of the nicotinic acetylcholine receptor channel. J. Neurosci. 9, 884-892 (1989).
114. Eisenberg, R. Computing the field in proteins and channels. J. Membr. Biol. 150, 1-25 (1996).
115. Green, M. E. & Lu, J. Monte-Carlo simulation of the effects of charges on water and ions in a tapered pore. J. Colloid Interface Sci. 171, 117-126 (1995).
116. + selectivity filter. Nature 414, 37-42 (2001).
117. +channel-Fab complex at 2.0 A resolution. Nature 414, 43-48 (2001).
118. Villarroel, A., Herlitze, S., Koenen, M. & Sakmann, B. Location of a threonine residue in the α-subunit M2 transmembrane segment that determines the ion flow through the acetylcholine receptor channel. Proc. R. Soc. Lond. B 243, 69-74 (1991).
119. Konno, T et al. Rings of anionic amino acids as structural determinants of ion selectivity in the acetylcholine receptor channel. Proc. R. Soc. Lond. B 244, 69-79 (1991).
120. Imoto, K et al. A ring of uncharged polar amino acids as a component of channel constriction in the nicotinic acetylcholine receptor. FEBS Lett. 289, 193-200 (1991).
121. Cohen, B. N., Labarca, C., Davidson, N. & Lester, H. A. Mutations in M2 alter the selectivity of the mouse nicotinic acetylcholine receptor for organic and alkali metal cations. J. Gen. Physiol. 100, 373-400 (1992).
122. Corringer, P. J. et al. Mutational analysis of the charge selectivity filter of the α7 nicotinic acetylcholine receptor. Neuron 22, 831-843 (1999).
123. Wilson, G. G. & Karlin, A. The location of the gate in the acetylcholine receptor channel. Neuron 20, 1269-1281 (1998).
124. Wilson, G. G. & Karlin, A. Acetylcholine channel structure in the resting, open, and desensitized states probed with the substituted-cysteine-accessibility method. Proc. Natl Acad. Sci. USA 98, 1241-1248 (2001).
125. Imoto, K et al. Location of a 8-subunit region determining ion transport through the acetylcholine receptor channel. Nature 324, 670-674 (1986).
126. Imoto, K et al. Rings of negatively charged amino acids determine the acetylcholine receptor channel conductance. Nature 335, 645-648 (1988).
127. 3H]chlorpromazine. Proc. Natl Acad. Sci. USA 83, 2719-2723 (1986).
128. Giraudat, J. et al. Structure of the high-affinity binding site for noncompetitive blockers of the acetylcholine receptor: pH]chlorpromazine labels homologous residues in the β and δ chains. Biochemistry 26, 2410-2418 (1987).
129. Hucho, F., Oberthur, W. & Lottspeich, F. The ion channel of the nicotinic acetylcholine receptor is formed by the homologous helices M II of the receptor subunits. FEBS Lett. 205, 137-142 (1986).
130. 3H]quinacrine azide in the active state of the nicotinic acetylcholine receptor. J. Biol. Chem. 265, 11017-11029 (1990).
131. Akabas, M. H., Stauffer, D. A., Xu, M. & Karlin, A. Acetylcholine receptor channel structure probed in cysteine-substitution mutants. Science 258, 307-310 (1992).
132. Pascual, J. M. & Karlin, A. State-dependent accessibility and electrostatic potential in the channel of the acetylcholine receptor: inferences from rates of reaction of thiosulfonates with substituted cysteines in the M2 segment of the α subunit. J. Gen. Physiol. 111, 717-739 (1998).
133. Wilson, G. G., Pascual, J. M., Brooijmans, N., Murray, D. & Karlin, A. The intrinsic electrostatic potential and the intermediate ring of charge in the acetylcholine receptor channel. J. Gen. Physiol. 115, 93-106 (2000).
134. Heidmann, T & Changeux, J. P. Time-resolved photolabeling by the noncompetitive blocker chlorpromazine of the acetylcholine receptor in its transiently open and closed ion channel conformations. Proc. Natl Acad. Sci. USA 81, 1897-1901 (1984).
135. Cox, R. N., Kaldany R. R., DiPaola, M. & Karlin, A. Time- resolved photolabeling by quinacrine azide of a noncompetitive inhibitor site of the nicotinic acetylcholine receptor in a transient, agonist-induced state. J. Biol. Chem. 260, 7186-7193 (1985).
136. White, B. H. & Cohen, J. B. Agonist-induced changes in the structure of the acetylcholine receptor M2 regions revealed by photoincorporation of an uncharged nicotinic noncompetitive antagonist. J. Biol. Chem. 267, 15770-15783 (1992).
137. McCarthy, M. P. & Moore, M. A. Effects of lipids and detergents on the conformation of the nicotinic acetylcholine receptor from Torpedo californica. J. Biol. Chem. 267, 7655-7663 (1992).
138. Bertrand, D., Galzi, J. L., Devillers-Thiery, A., Bertrand, S. & Changeux, J. P. Mutations at two distinct sites within the channel domain M2 alter calcium permeability of neuronal α7 nicotinic receptor. Proc. Natl Acad. Sci. USA 90, 6971-6975 (1993).
139. Labarca, C. et al. Channel gating governed symmetrically by conserved leucine residues in the M2 domain of nicotinic receptors. Nature 376, 514-516 (1995).
140. Filatov, G. N. & White, M. M. The role of conserved leucines in the M2 domain of the acetylcholine receptor in channel gating. Mol. Pharmacol. 48, 379-384 (1995).
141. Kosolapov, A. V, Filatov, G. N. & White, M. M. Acetylcholine receptor gating is influenced by the polarity of amino acids at position 9' in the M2 domain. J. Membr. Biol. 174, 191-197 (2000).
142. Grosman, C. & Auerbach, A. Asymmetric and independent contribution of the second transmembrane segment 12' residues to diliganded gating of acetylcholine receptor channels: a single-channel study with choline as the agonist. J. Gen. Physiol. 115, 637-651 (2000).
143. Grosman, C., Salamone, F. N., Sine, S. M. & Auerbach, A. The extracellular linker of muscle acetylcholine receptor channels is a gating control element. J. Gen. Physiol. 116, 327-340 (2000).
144. Wang, H. L. et al. Acetylcholine receptor M3 domain: stereochemical and volume contributions to channel gating. Nature Neurosci. 2, 226-233 (1999).
145. Bouzat, C., Barrantes, F. & Sine, S. Nicotinic receptor fourth transmembrane domain: hydrogen bonding by conserved threonine contributes to channel gating kinetics. J. Gen. Physiol. 115, 663-672 (2000).
146. DaCosta, C. J., Ogrel, A. A., McCardy, E. A., Blanton, M. P & Baenziger, J. E. Lipid-protein interactions at the nicotinic acetylcholine receptor: a functional coupling between nicotinic receptors and phosphatidic acid-containing lipid bilayers. J. Biol. Chem. 277, 201-208 (2002).
147. Wang, H. L. et al. Fundamental gating mechanism of nicotinic receptor channel revealed by mutation causing a congenital myasthenic syndrome. J. Gen. Physiol. 116, 449-462 (2000).
148. Unwin, N. Acetylcholine receptor channel imaged in the open state. Nature 373, 37-43 (1995).
149. Takahama, K. & Klee, M. R. Voltage clamp analysis of the kinetics of piperidine-induced chloride current in isolated Aplysia neurons. Naunyn Schmiedebergs Arch. Pharmacol. 342, 575-581 (1990).
150. Kehoe, J. & McIntosh, J. M. Two distinct nicotinic receptors, one pharmacologically similar to the vertebrate α7-containing receptor, mediate Cl currents in Aplysia neurons. J. Neurosci. 18, 8198-8213 (1998).
151. Adams, D. J., Dwyer, T. M. & Hille, B. The permeability of endplate channels to monovalent and divalent metal cations. J. Gen. Physiol. 75, 493-510 (1980).
152. Lewis, C. A. & Stevens, C. F Acetylcholine receptor channel ionic selectivity: ions experience an aqueous environment. Proc. Natl Acad. Sci. USA 80, 6110-6113 (1983).
153. Fieber, L. A. & Adams, D. J. Acetylcholine-evoked currents in cultured neurones dissociated from rat parasympathetic cardiac ganglia. J. Physiol. (Lond.) 434, 215-237 (1991).
154. Vernino, S., Amador, M., Luetje, C. W., Patrick, J. & Dani, J. A. Calcium modulation and high calcium permeability of neuronal nicotinic acetylcholine receptors. Neuron 8, 127-134 (1992).
155. Katz, E. et al. High calcium permeability and calcium block of the α9 nicotinic acetylcholine receptor. Hear. Res. 141, 117-128 (2000).
156. + permeability ratios of nicotinic acetylcholine receptors are reduced by mutations near the intracellular end of the M2 region. J. Gen. Physiol. 99, 545-572 (1992).
157. Villarroel, A., Herlitze, S., Witzemann, V, Koenen, M. & Sakmann, B. Asymmetry of the rat acetylcholine receptor subunits in the narrow region of the pore. Proc. R. Soc. Lond. B 249, 317-324 (1992).
158. 3A receptor from cationic to anionic reveals a conserved feature of the ligand-gated ion channel superfamily. J. Biol. Chem. 276, 10977-10983 (2001).
159. Keramidas, A., Moorhouse, A. J., French, C. R., Schofield, P. R. & Barry, P. H. M2 pore mutations convert the glycine receptor channel from being anion- to cation-selective. Biophys. J. 79, 247-259 (2000).
160. Adcock, C., Smith, G. R. & Sansom, M. S. The nicotinic acetylcholine receptor: from molecular model to single- channel conductance. Eur. Biophys. J. 29, 29-37 (2000).
161. Yakel, J. L., Lagrutta, A., Adelman, J. P & North, R. A. Single amino acid substitution affects desensitization of the 5-hydroxytryptamine type 3 receptor expressed in Xenopus oocytes. Proc. Natl Acad. Sci. USA 90, 5030-5033 (1993).
162. Areceptor α1 subunit. J. Gen. Physiol. 107, 195-205 (1996)
163. Karlin, A. & Akabas, M. H. Substituted-cysteine accessibility method. Metfiods Enzymol. 293, 123-145 (1998).
164. Javitch, J. A., Li, X., Kaback, J. & Karlin, A. A cysteine residue in the third membrane-spanning segment of the human D2 dopamine receptor is exposed in the binding-site crevice. Proc. Natl Acad. Sci. USA 91, 10355-10359 (1994).
165. Javitch, J. A., Fu, D., Chen, J. & Karlin, A. Mapping the binding-site crevice of the dopamine D2 receptor by the substituted-cysteine accessibility method. Neuron 14, 825-831 (1995).
166. Bruice, T. W. & Kenyon, G. L. Novel alkyl alkanethiosulfonate sulfhydryl reagents. Modification of derivatives of L-cysteine. J. Protein Chem. 1, 47-58 (1982).
167. Roberts, D. D., Lewis, S. D., Ballou, D. P., Olson, S. T & Shafer, J. A. Reactivity of small thiolate anions and cysteine-25 in papain toward methyl methanethiosulfonate. Biochemistry 25, 5595-5601 (1986).
168. Kaback, H. R. A molecular mechanism for energy coupling in a membrane transport protein, the lactose permease of Escherichia coli. Proc. Natl Acad. Sci. USA 94, 5539-5543 (1997).