|
|
|
|
|
|
|
||
ARTICLE |
Correspondence to Steven M. Sine: sine{at}mayo.edu
We examined functional consequences of intrasubunit contacts in the nicotinic receptor 
subunit using single channel kinetic analysis, site-directed mutagenesis, and structural modeling. At the periphery of the ACh binding site, our structural model shows that side chains of the conserved residues K145, D200, and Y190 converge to form putative electrostatic interactions. Structurally conservative mutations of each residue profoundly impair gating of the receptor channel, primarily by slowing the rate of channel opening. The combined mutations D200N and K145Q impair channel gating to the same extent as either single mutation, while K145E counteracts the impaired gating due to D200K, further suggesting electrostatic interaction between these residues. Interpreted in light of the crystal structure of acetylcholine binding protein (AChBP) with bound carbamylcholine (CCh), the results suggest in the absence of ACh, K145 and D200 form a salt bridge associated with the closed state of the channel. When ACh binds, Y190 moves toward the center of the binding cleft to stabilize the agonist, and its aromatic hydroxyl group approaches K145, which in turn loosens its contact with D200. The positional changes of K145 and D200 are proposed to initiate the cascade of perturbations that opens the receptor channel: the first perturbation is of ß-strand 7, which harbors K145 and is part of the signature Cys-loop, and the second is of ß-strand 10, which harbors D200 and connects to the M1 domain. Thus, interplay between these three conserved residues relays the initial conformational change from the ACh binding site toward the ion channel.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  A. J. Thompson, M. Lochner, and S. C. R. Lummis Loop B Is a Major Structural Component of the 5-HT3 Receptor Biophys. J., December 15, 2008; 95(12): 5728 - 5736. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. A. Horenstein, F. M. Leonik, and R. L. Papke Multiple Pharmacophores for the Selective Activation of Nicotinic {alpha}7-Type Acetylcholine Receptors Mol. Pharmacol., December 1, 2008; 74(6): 1496 - 1511. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. P. Venkatachalan and C. Czajkowski A conserved salt bridge critical for GABAA receptor function and loop C dynamics PNAS, September 9, 2008; 105(36): 13604 - 13609. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Y. Lee, C. R. Free, and S. M. Sine Nicotinic Receptor Interloop Proline Anchors {beta}1-{beta}2 and Cys loops in Coupling Agonist Binding to Channel Gating J. Gen. Physiol., August 1, 2008; 132(2): 265 - 278. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Bouzat, M. Bartos, J. Corradi, and S. M. Sine The Interface between Extracellular and Transmembrane Domains of Homomeric Cys-Loop Receptors Governs Open-Channel Lifetime and Rate of Desensitization J. Neurosci., July 30, 2008; 28(31): 7808 - 7819. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Purohit and A. Auerbach Acetylcholine Receptor Gating: Movement in the {alpha}-Subunit Extracellular Domain J. Gen. Physiol., November 26, 2007; 130(6): 569 - 579. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. A. Gay and J. L. Yakel Gating of nicotinic ACh receptors; new insights into structural transitions triggered by agonist binding that induce channel opening J. Physiol., November 1, 2007; 584(3): 727 - 733. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Cheng, I. Ivanov, H. Wang, S. M. Sine, and J. A. McCammon Nanosecond-Timescale Conformational Dynamics of the Human {alpha}7 Nicotinic Acetylcholine Receptor Biophys. J., October 15, 2007; 93(8): 2622 - 2634. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. T. McLaughlin, J. Fu, and R. L. Rosenberg Agonist-Driven Conformational Changes in the Inner beta-Sheet of {alpha}7 Nicotinic Receptors Mol. Pharmacol., May 1, 2007; 71(5): 1312 - 1318. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Mukhtasimova and S. M. Sine An Intersubunit Trigger of Channel Gating in the Muscle Nicotinic Receptor J. Neurosci., April 11, 2007; 27(15): 4110 - 4119. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. A. Horenstein, T. J. McCormack, C. Stokes, K. Ren, and R. L. Papke Reversal of Agonist Selectivity by Mutations of Conserved Amino Acids in the Binding Site of Nicotinic Acetylcholine Receptors J. Biol. Chem., February 23, 2007; 282(8): 5899 - 5909. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. T. Young, L. M. Broad, R. Zwart, P. C. Astles, M. Bodkin, E. Sher, and N. S. Millar Species Selectivity of a Nicotinic Acetylcholine Receptor Agonist Is Conferred by Two Adjacent Extracellular beta4 Amino Acids that Are Implicated in the Coupling of Binding to Channel Gating Mol. Pharmacol., February 1, 2007; 71(2): 389 - 397. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Corradi, G. Spitzmaul, M. J. De Rosa, M. Costabel, and C. Bouzat Role of Pairwise Interactions between M1 and M2 Domains of the Nicotinic Receptor in Channel Gating Biophys. J., January 1, 2007; 92(1): 76 - 86. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Gao, G. Mer, M. Tonelli, S. B. Hansen, T. P. Burghardt, P. Taylor, and S. M. Sine Solution NMR of Acetylcholine Binding Protein Reveals Agonist-Mediated Conformational Change of the C-Loop Mol. Pharmacol., October 1, 2006; 70(4): 1230 - 1235. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. T. McLaughlin, J. Fu, A. D. Sproul, and R. L. Rosenberg Role of the Outer beta-Sheet in Divalent Cation Modulation of {alpha}7 Nicotinic Receptors Mol. Pharmacol., July 1, 2006; 70(1): 16 - 22. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Mercado and C. Czajkowski Charged Residues in the {alpha}1 and beta2 Pre-M1 Regions Involved in GABAA Receptor Activation J. Neurosci., February 15, 2006; 26(7): 2031 - 2040. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Criado, J. Mulet, J. A. Bernal, S. Gerber, S. Sala, and F. Sala Mutations of a Conserved Lysine Residue in the N-Terminal Domain of {alpha}7 Nicotinic Receptors Affect Gating and Binding of Nicotinic Agonists Mol. Pharmacol., December 1, 2005; 68(6): 1669 - 1677. [Abstract] [Full Text] [PDF]
|
|
|
|
