2V96

Structure of the unphotolysed complex of TcAChE with 1-(2- nitrophenyl)-2,2,2-trifluoroethyl-arsenocholine at 100K

Summary for 2V96

• Entry DOI: 10.2210/pdb2v96/pdb
• Related: 1ACJ 1ACL 1AMN 1AX9 1CFJ 1DX6 1E3Q 1E66 1EA5 1EEA 1EVE 1FSS 1GPK 1GPN 1GQR 1GQS 1H22 1H23 1HBJ 1JGA 1JGB 1JJB 1OCE 1ODC 1QID 1QIE 1QIF 1QIG 1QIH 1QII 1QIJ 1QIK 1QIM 1QTI 1SOM 1U65 1UT6 1VOT 1VXO 1VXR 1W4L 1W6R 1W75 1W76 1ZGB 1ZGC 2ACE 2ACK 2C4H 2C58 2C5F 2C5G 2CEK 2CKM 2CMF 2DFP 2J3D 2J3Q 2J4F 2V97 2V98 3ACE 4ACE
• Descriptor: ACETYLCHOLINESTERASE, 1-(2-nitrophenyl)-2,2,2-trifluoroethyl]-arsenocholine, 2-acetamido-2-deoxy-beta-D-glucopyranose, ... (4 entities in total)
• Functional Keywords: serine esterase, alternative splicing, acetylcholinesterase caged compounds kinetic crystallography partial q-weighted difference refinement backdoor, neurotransmitter degradation, lipoprotein, glycoprotein, cell junction, synapse, membrane, hydrolase, gpi-anchor
• Biological source: TORPEDO CALIFORNICA (PACIFIC ELECTRIC RAY)
• Total number of polymer chains: 2
• Total formula weight: 123834.71

Authors

Colletier, J.-P.,Sanson, B.,Royant, A.,Specht, A.,Nachon, F.,Masson, P.,Zaccai, G.,Sussman, J.L.,Goeldner, M.,Silman, I.,Bourgeois, D.,Weik, M. (deposition date: 2007-08-22, release date: 2007-11-20, Last modification date: 2024-11-20)

Primary citation

Colletier, J.-P.,Royant, A.,Specht, A.,Sanson, B.,Nachon, F.,Masson, P.,Zaccai, G.,Sussman, J.L.,Goeldner, M.,Silman, I.,Bourgeois, D.,Weik, M.
Use of a 'Caged' Analog to Study Traffic of Choline within Acetylcholinesterase by Kinetic Crystallography
Acta Crystallogr.,Sect.D, 63:1115-, 2007

PubMed Abstract: Acetylcholinesterase plays a crucial role in nerve-impulse transmission at cholinergic synapses. The apparent paradox that it displays high turnover despite its active site being buried raises cogent questions as to how the traffic of substrates and products to and from the active site can occur so rapidly in such circumstances. Here, a kinetic crystallography strategy aimed at structurally addressing the issue of product traffic in acetylcholinesterase is presented, in which UV-laser-induced cleavage of a photolabile precursor of the enzymatic product analogue arsenocholine, 'caged' arsenocholine, is performed in a temperature-controlled X-ray crystallography regime. The 'caged' arsenocholine was shown to bind at both the active and peripheral sites of acetylcholinesterase. UV irradiation of a complex with acetylcholinesterase during a brief temperature excursion from 100 K to room temperature is most likely to have resulted in a decrease in occupancy by the caged compound. Microspectrophotometric experiments showed that the caged compound had indeed been photocleaved. It is proposed that a fraction of the arsenocholine molecules released within the crystal had been expelled from both the active and the peripheral sites. Partial q-weighted difference refinement revealed a relative movement of the two domains in acetylcholinesterase after photolysis and the room-temperature excursion, resulting in an increase in the active-site gorge volume of 30% and 35% in monomers A and B of the asymmetric unit, respectively. Moreover, an alternative route to the active-site gorge of the enzyme appeared to open. This structural characterization of acetylcholinesterase 'at work' is consistent with the idea that choline exits from the enzyme after catalysis either via the gorge or via an alternative 'backdoor' trajectory.

PubMed: 18007027
DOI: 10.1107/S0907444907044472

Experimental method

X-RAY DIFFRACTION (2.4 Å)