1
|
Trapp M, Trovaslet M, Nachon F, Koza MM, van Eijck L, Hill F, Weik M, Masson P, Tehei M, Peters J. Energy Landscapes of Human Acetylcholinesterase and Its Huperzine A-Inhibited Counterpart. J Phys Chem B 2012. [DOI: 10.1021/jp304704h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marcus Trapp
- Comissariat
à l’Energie
Atomique, Institut de Biologie Structurale, F-38054 Grenoble, France
- Centre National De La Recherche Scientifique, UMR5075, F-38027 Grenoble,
France
- Université Joseph Fourier, UFR PhITEM, F-38041 Grenoble Cédex
9, France
- Institut Laue Langevin, F-38042 Grenoble Cédex
9, France
| | - Marie Trovaslet
- Institut de Recherche Biomédicale des Armées, F-38700 La Tronche,
France
| | - Florian Nachon
- Institut de Recherche Biomédicale des Armées, F-38700 La Tronche,
France
| | - Marek M. Koza
- Institut Laue Langevin, F-38042 Grenoble Cédex
9, France
| | - Lambert van Eijck
- Delft University of Technology, Faculty of Applied Sciences, RST/NPM2
Mekelweg 15, 2629JB Delft Netherlands
| | - Flynn Hill
- School of Chemistry and
Centre for
Medical Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Martin Weik
- Comissariat
à l’Energie
Atomique, Institut de Biologie Structurale, F-38054 Grenoble, France
- Centre National De La Recherche Scientifique, UMR5075, F-38027 Grenoble,
France
- Université Joseph Fourier, UFR PhITEM, F-38041 Grenoble Cédex
9, France
| | - Patrick Masson
- Comissariat
à l’Energie
Atomique, Institut de Biologie Structurale, F-38054 Grenoble, France
- Centre National De La Recherche Scientifique, UMR5075, F-38027 Grenoble,
France
- Université Joseph Fourier, UFR PhITEM, F-38041 Grenoble Cédex
9, France
- Institut de Recherche Biomédicale des Armées, F-38700 La Tronche,
France
| | - Moeava Tehei
- School of Chemistry and
Centre for
Medical Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Australian Institute of Nuclear Science and Engineering (AINSE), Menai, NSW,
Australia
| | - Judith Peters
- Comissariat
à l’Energie
Atomique, Institut de Biologie Structurale, F-38054 Grenoble, France
- Centre National De La Recherche Scientifique, UMR5075, F-38027 Grenoble,
France
- Université Joseph Fourier, UFR PhITEM, F-38041 Grenoble Cédex
9, France
- Institut Laue Langevin, F-38042 Grenoble Cédex
9, France
| |
Collapse
|
2
|
Jun D, Musilova L, Kuca K, Kassa J, Bajgar J. Potency of several oximes to reactivate human acetylcholinesterase and butyrylcholinesterase inhibited by paraoxon in vitro. Chem Biol Interact 2008; 175:421-4. [DOI: 10.1016/j.cbi.2008.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 04/30/2008] [Accepted: 05/01/2008] [Indexed: 10/22/2022]
|
3
|
Millard CB, Kryger G, Ordentlich A, Greenblatt HM, Harel M, Raves ML, Segall Y, Barak D, Shafferman A, Silman I, Sussman JL. Crystal structures of aged phosphonylated acetylcholinesterase: nerve agent reaction products at the atomic level. Biochemistry 1999; 38:7032-9. [PMID: 10353814 DOI: 10.1021/bi982678l] [Citation(s) in RCA: 223] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Organophosphorus acid anhydride (OP) nerve agents are potent inhibitors which rapidly phosphonylate acetylcholinesterase (AChE) and then may undergo an internal dealkylation reaction (called "aging") to produce an OP-enzyme conjugate that cannot be reactivated. To understand the basis for irreversible inhibition, we solved the structures of aged conjugates obtained by reaction of Torpedo californica AChE (TcAChE) with diisopropylphosphorofluoridate (DFP), O-isopropylmethylphosponofluoridate (sarin), or O-pinacolylmethylphosphonofluoridate (soman) by X-ray crystallography to 2.3, 2.6, or 2.2 A resolution, respectively. The highest positive difference density peak corresponded to the OP phosphorus and was located within covalent bonding distance of the active-site serine (S200) in each structure. The OP-oxygen atoms were within hydrogen-bonding distance of four potential donors from catalytic subsites of the enzyme, suggesting that electrostatic forces significantly stabilize the aged enzyme. The active sites of aged sarin- and soman-TcAChE were essentially identical and provided structural models for the negatively charged, tetrahedral intermediate that occurs during deacylation with the natural substrate, acetylcholine. Phosphorylation with DFP caused an unexpected movement in the main chain of a loop that includes residues F288 and F290 of the TcAChE acyl pocket. This is the first major conformational change reported in the active site of any AChE-ligand complex, and it offers a structural explanation for the substrate selectivity of AChE.
Collapse
Affiliation(s)
- C B Millard
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Silman I, Millard CB, Ordentlich A, Greenblatt HM, Harel M, Barak D, Shafferman A, Sussman JL. A preliminary comparison of structural models for catalytic intermediates of acetylcholinesterase. Chem Biol Interact 1999; 119-120:43-52. [PMID: 10421437 DOI: 10.1016/s0009-2797(99)00012-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Determination of the three dimensional structure of Torpedo Californica acetylcholinesterase (TcAChE) provided an experimental tool for directly visualizing interaction of AChE with cholinesterase inhibitors of fundamental, pharmacological and toxicological interest. The structure revealed that the active site is located near the bottom of a deep and narrow gorge lined with 14 conserved aromatic amino acids. The structure of a complex of TcAChE with the powerful 'transition state analog' inhibitor, TMTFA, suggested that its orientation in the experimentally determined structure was very similar to that proposed for the natural substrate, acetylcholine, by manual docking. The array of enzyme-ligand interactions visualized in the TMFTA complex also are expected to envelope the unstable TI that forms with acetylcholine during acylation, and to sequester it from solvent. In our most recent studies, the crystal structures of several 'aged' conjugates of TcAChE obtained with OP nerve agents have been solved and compared with that of the native enzyme. The methylphosphonylated-enzyme obtained by reaction with soman provides a useful structural analog for the TI that forms during deacylation after the reaction of TcAChE with acetylcholine. By comparing these structures, we conclude that the same 'oxyanion hole' residues, as well as the aromatic side chains constituting the 'acyl pocket', participate in acylation (TMTFA-AChE) and deacylation (OP-AChE), and that AChE can accommodate both TIs at the bottom of the gorge without major conformational movements.
Collapse
Affiliation(s)
- I Silman
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Froment MT, Lockridge O, Masson P. Resistance of butyrylcholinesterase to inactivation by ultrasound: effects of ultrasound on catalytic activity and subunit association. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1387:53-64. [PMID: 9748500 DOI: 10.1016/s0167-4838(98)00105-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects of 20 kHz ultrasound on catalytic activity and structure of the tetramer of wild-type human butyrylcholinesterase (BChE) from plasma and recombinant D70G mutant enzyme were studied at constant temperature. Effects on catalytic properties of both enzymes were investigated by kinetic analysis under ultrasound irradiation using a neutral substrate (o-nitrophenylbutyrate), a positively charged substrate (butyrylthiocholine), and a negatively charged substrate (aspirin). Effects on structure of highly purified wild-type BChE were followed by gel electrophoresis and activity measurements at Vmax after ultrasound treatment. Unlike hydrostatic pressure, mild ultrasound had moderate effects on catalytic parameters of BChE-catalyzed hydrolysis of substrates. For both wild-type and D70G, Km increased slightly with butyrylthiocholine and o-nitrophenylbutyrate under ultrasound irradiation, suggesting that these effects of ultrasound were not due to the periodic variation of pressure but rather to shear forces that took off substrate from the peripheral site and altered diffusion to the active site. By contrast, affinity of the D70G mutant for aspirin slightly increased with ultrasound power, suggesting that ultrasound-induced microstreaming unmasked peripheral residues involved in recognition and initial binding of the negatively charged substrate. Results support the contention that Km is a composite affinity constant, including dissociation constant of the first encounter enzyme-substrate complex on the peripheral site. Small changes in catalytic activity may have resulted from ultrasound-induced subtle conformational changes altering the active site reactivity. Short ultrasound irradiation induced a faint transient enzyme activation, but prolonged irradiation caused partial dissociation of the tetrameric enzyme and irreversible inactivation. Partial dissociation was related to enzyme microheterogeneity, i.e., nicked (C-terminal segment depleted) tetramers were less stable than native tetramers. The resistance of the native tetramer to ultrasound-induced dissociation was ascribed to the existence of an aromatic amino acid array on the apolar side of the C-terminal helical segment of subunits, the four subunits being held together in a four-helix bundle containing the aromatic zipper motifs. Aromatic/aromatic interactions between the four helical segments are thought to be enhanced by ultrasound-generated pressure.
Collapse
Affiliation(s)
- M T Froment
- Centre de Recherches du Service de Santé des Armées, Unité d'Enzymologie, BP 87, 38702 La Tronche Cedex, France
| | | | | |
Collapse
|
6
|
Bencsura A, Enyedy IY, Kovach IM. Probing the Active Site of Acetylcholinesterase by Molecular Dynamics of Its Phosphonate Ester Adducts. J Am Chem Soc 1996. [DOI: 10.1021/ja952406v] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Akos Bencsura
- Contribution from the Department of Chemistry, The Catholic University of America, Washington, DC 20064
| | - Istvan Y. Enyedy
- Contribution from the Department of Chemistry, The Catholic University of America, Washington, DC 20064
| | - Ildiko M. Kovach
- Contribution from the Department of Chemistry, The Catholic University of America, Washington, DC 20064
| |
Collapse
|
7
|
Gróf P, Aslanian D, Rontó G. Changes of phage T7 nucleoprotein structure at low ionic strength. A Raman spectroscopic study. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1289:95-104. [PMID: 8605239 DOI: 10.1016/0304-4165(95)00151-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To detect changes in DNA and/or protein structures of phage T7 under different ionic strength, Raman spectra of phage T7 have been recorded in solutions of three different NaCl + Tris concentrations. Iterative Jansson-Van Cittert deconvolution, as well as decomposition methods have been used to quantify changes in DNA structure. Significant modifications in ratios of contributions from 675 and 685 per cm vibrations, as well as in the DNA backbone vibrations, characteristic for B-DNA, near 835 per cm frequency have been found. Changes of the base electronic structure were identified in the interval between 1280 and 1400 cm(-1). Estimation of the overall protein structure suggests predominant beta-sheet content.
Collapse
Affiliation(s)
- P Gróf
- Institute of Biophysics, Semmelweis Medical University, Budapest, Hungary
| | | | | |
Collapse
|
8
|
Pressure-induced molten globule states of proteins. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0921-0423(06)80021-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|