Substrate inhibition of acetylcholinesterase: residues affecting signal transduction from the surface to the catalytic center.
Avigdor Shafferman,Baruch Velan,Arie Ordentlich,C. Kronman,Haim Grosfeld,M Leitner,Yehuda Flashner,Sara Cohen,Dov Barak,Naomi Ariel +9 more
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TLDR
It is proposed that binding of acetylcholine, on the surface of AChE, may trigger sequence of conformational changes extending from the peripheral anionic site through W286 to D74, at the entrance of the ‘gorge’, and down to the catalytic center (through Y341 to F338 and Y337).Abstract:
Amino acids located within and around the 'active site gorge' of human acetylcholinesterase (AChE) were substituted. Replacement of W86 yielded inactive enzyme molecules, consistent with its proposed involvement in binding of the choline moiety in the active center. A decrease in affinity to propidium and a concomitant loss of substrate inhibition was observed in D74G, D74N, D74K and W286A mutants, supporting the idea that the site for substrate inhibition and the peripheral anionic site overlap. Mutations of amino acids neighboring the active center (E202, Y337 and F338) resulted in a decrease in the catalytic and the apparent bimolecular rate constants. A decrease in affinity to edrophonium was observed in D74, E202, Y337 and to a lesser extent in F338 and Y341 mutants. E202, Y337 and Y341 mutants were not inhibited efficiently by high substrate concentrations. We propose that binding of acetylcholine, on the surface of AChE, may trigger sequence of conformational changes extending from the peripheral anionic site through W286 to D74, at the entrance of the 'gorge', and down to the catalytic center (through Y341 to F338 and Y337). These changes, especially in Y337, could block the entrance/exit of the catalytic center and reduce the catalytic efficiency of AChE.read more
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Molecular and cellular biology of cholinesterases
TL;DR: In this article, the authors propose a method to identify the root cause of a problem.Abbreviations: [2]... ].., [3]
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Structure of acetylcholinesterase complexed with E2020 (Aricept): implications for the design of new anti-Alzheimer drugs.
TL;DR: This study shows that the design of E2020 took advantage of several important features of the active-site gorge of AChE to produce a drug with both high affinity for A cholinesterase and a high degree of selectivity for A ChE versus butyrylcholinestersterase (BChE).
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Structural insights into ligand interactions at the acetylcholinesterase peripheral anionic site
TL;DR: These structures of AChE provide templates for designing compounds directed to the enzyme surface that modulate specific surface interactions controlling catalytic activity and non‐catalytic heterologous protein associations.
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Three distinct domains in the cholinesterase molecule confer selectivity for acetyl- and butyrylcholinesterase inhibitors.
TL;DR: By examining inhibitor interactions with single and multiple site-specific mutants of mouse acetylcholinesterase, three distinct domains are identified that are responsible for conferring selectivity for acetyl- and butyrylcholiersterase inhibitors.
References
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A new and rapid colorimetric determination of acetylcholinesterase activity.
TL;DR: A photometric method for determining acetylcholinesterase activity of tissue extracts, homogenates, cell suspensions, etc., has been described and Kinetic constants determined by this system for erythrocyte eholinesterases are presented.
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Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells.
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Atomic structure of acetylcholinesterase from Torpedo californica: a prototypic acetylcholine-binding protein
Joel L. Sussman,Michal Harel,Felix Frolow,Christian Oefner,Adrian Goldman,Lilly Toker,Israel Silman +6 more
TL;DR: Modeling of acetylcholine binding to the enzyme suggests that the quaternary ammonium ion is bound not to a negatively charged "anionic" site, but rather to some of the 14 aromatic residues that line the gorge.
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Transfer of purified herpes virus thymidine kinase gene to cultured mouse cells.
TL;DR: The results prove the usefulness of transfection assays as a means for the bioassay and isolation of restriction fragments carrying specific genetic information and cells expressing HSV-1 tk may also provide a useful model system for the detailed analysis of eucaryotic and viral gene regulation.
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Acetylcholine binding by a synthetic receptor: implications for biological recognition
TL;DR: The neurotransmitter acetylcholine is bound with 50-micromolar affinity by a completely synthetic receptor (host) comprising primarily aromatic rings, and similar interactions may be involved in biological recognition of ACh and other choline derivatives.