HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) An addition or correction has been published Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Radic, Z. Articles by Taylor, P. Search for Related Content PubMed PubMed Citation Articles by Radic, Z. Articles by Taylor, P. Social Bookmarking                      What's this?

Volume 272, Number 37, Issue of September 12, 1997 pp. 23265-23277
©1997 by The American Society for Biochemistry and Molecular Biology, Inc.

Electrostatic Influence on the Kinetics of Ligand Binding to Acetylcholinesterase
DISTINCTIONS BETWEEN ACTIVE CENTER LIGANDS AND FASCICULIN

(Received for publication, April 16, 1997, and in revised form, June 19, 1997)

Zoran Radi , Paul D. Kirchhoff ^§ , Daniel M. Quinn ^¶ , J. Andrew McCammon ^§ and Palmer Taylor

From the Departments of  Pharmacology and of ^§ Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0636 and the ^¶ Department of Chemistry, University of Iowa, Iowa City, Iowa 52242

To explore the role that surface and active center charges play in electrostatic attraction of ligands to the active center gorge of acetylcholinesterase (AChE), and the influence of charge on the reactive orientation of the ligand, we have studied the kinetics of association of cationic and neutral ligands with the active center and peripheral site of AChE. Electrostatic influences were reduced by sequential mutations of six surface anionic residues outside of the active center gorge (Glu-84, Glu-91, Asp-280, Asp-283, Glu-292, and Asp-372) and three residues within the active center gorge (Asp-74 at the rim and Glu-202 and Glu-450 at the base). The peripheral site ligand, fasciculin 2 (FAS2), a peptide of 6.5 kDa with a net charge of +4, shows a marked enhancement of rate of association with reduction in ionic strength, and this ionic strength dependence can be markedly reduced by progressive neutralization of surface and active center gorge anionic residues. By contrast, neutralization of surface residues only has a modest influence on the rate of cationic m-trimethylammoniotrifluoroacetophenone (TFK⁺) association with the active serine, whereas neutralization of residues in the active center gorge has a marked influence on the rate but with little change in the ionic strength dependence. Brownian dynamics calculations for approach of a small cationic ligand to the entrance of the gorge show the influence of individual charges to be in quantitative accord with that found for the surface residues. Anionic residues in the gorge may help to orient the ligand for reaction or to trap the ligand. Bound FAS2 on AChE not only reduces the rate of TFK⁺ reaction with the active center but inverts the ionic strength dependence for the cationic TFK⁺ association with AChE. Hence it appears that TFK⁺ must traverse an electrostatic barrier at the gorge entry imparted by the bound FAS2 with its net charge of +4.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. A. McCammon Darwinian biophysics: Electrostatics and evolution in the kinetics of molecular binding PNAS, May 12, 2009; 106(19): 7683 - 7684. [Full Text] [PDF]

				D. R. Dries and A. C. Newton Kinetic Analysis of the Interaction of the C1 Domain of Protein Kinase C with Lipid Membranes by Stopped-flow Spectroscopy J. Biol. Chem., March 21, 2008; 283(12): 7885 - 7893. [Abstract] [Full Text] [PDF]

				J. M. Alexander-Brett and D. H. Fremont Dual GPCR and GAG mimicry by the M3 chemokine decoy receptor J. Exp. Med., December 24, 2007; 204(13): 3157 - 3172. [Abstract] [Full Text] [PDF]

				B. Lu, X. Cheng, J. Huang, and J. A. McCammon Order N algorithm for computation of electrostatic interactions in biomolecular systems PNAS, December 19, 2006; 103(51): 19314 - 19319. [Abstract] [Full Text] [PDF]

				I. M.-P. y Valenzuela, R. I. Hume, E. Krejci, and M. Akaaboune In Vivo Regulation of Acetylcholinesterase Insertion at the Neuromuscular Junction J. Biol. Chem., September 9, 2005; 280(36): 31801 - 31808. [Abstract] [Full Text] [PDF]

				H. Dong, Y.-Y. Xiang, N. Farchi, W. Ju, Y. Wu, L. Chen, Y. Wang, B. Hochner, B. Yang, H. Soreq, et al. Excessive Expression of Acetylcholinesterase Impairs Glutamatergic Synaptogenesis in Hippocampal Neurons J. Neurosci., October 13, 2004; 24(41): 8950 - 8960. [Abstract] [Full Text] [PDF]

				A. E. Boyd, C. S. Dunlop, L. Wong, Z. Radic, P. Taylor, and D. A. Johnson Nanosecond Dynamics of Acetylcholinesterase Near the Active Center Gorge J. Biol. Chem., June 18, 2004; 279(25): 26612 - 26618. [Abstract] [Full Text] [PDF]

				J. Shi, A. E. Boyd, Z. Radic, and P. Taylor Reversibly Bound and Covalently Attached Ligands Induce Conformational Changes in the Omega Loop, Cys69-Cys96, of Mouse Acetylcholinesterase J. Biol. Chem., November 2, 2001; 276(45): 42196 - 42204. [Abstract] [Full Text] [PDF]

				J. G. Mandell, V. A. Roberts, M. E. Pique, V. Kotlovyi, J. C. Mitchell, E. Nelson, I. Tsigelny, and L. F. Ten Eyck Protein docking using continuum electrostatics and geometric fit Protein Eng. Des. Sel., February 1, 2001; 14(2): 105 - 113. [Abstract] [Full Text] [PDF]

				S. Freitag, V. Chu, J. E. Penzotti, L. A. Klumb, R. To, D. Hyre, I. Le Trong, T. P. Lybrand, R. E. Stenkamp, and P. S. Stayton A structural snapshot of an intermediate on the streptavidin-biotin dissociation pathway PNAS, July 20, 1999; 96(15): 8384 - 8389. [Abstract] [Full Text] [PDF]

				H.-X. Zhou, S. T. Wlodek, and J. A. McCammon Conformation gating as a mechanism for enzyme specificity PNAS, August 4, 1998; 95(16): 9280 - 9283. [Abstract] [Full Text] [PDF]

				H. Osaka, N. Sugiyama, and P. Taylor Distinctions in Agonist and Antagonist Specificity Conferred by Anionic Residues of the Nicotinic Acetylcholine Receptor J. Biol. Chem., May 22, 1998; 273(21): 12758 - 12765. [Abstract] [Full Text] [PDF]

				A. E. Boyd, A. B. Marnett, L. Wong, and P. Taylor Probing the Active Center Gorge of Acetylcholinesterase by Fluorophores Linked to Substituted Cysteines J. Biol. Chem., July 14, 2000; 275(29): 22401 - 22408. [Abstract] [Full Text] [PDF]

				Z. Radic' and P. Taylor Interaction Kinetics of Reversible Inhibitors and Substrates with Acetylcholinesterase and Its Fasciculin 2 Complex J. Biol. Chem., February 9, 2001; 276(7): 4622 - 4633. [Abstract] [Full Text] [PDF]