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Dadun > Depósito Académico > CIMA (Centro de Investigación Médica Aplicada) > Área de Terapia génica y Hepatología > Hepatología bioquímica > DA - CIMA - Terapia génica y Hepatología - Hepatología bioquímica - Artículos de revista >

Folding of dimeric methionine adenosyltransferase III: identification of two folding intermediates
Authors: Sanchez del Pino, M.M. (Manuel M.)
Perez-Mato, I. (Isabel)
Sanz, J.M. (Jesús M.)
Mato, J.M. (José María)
Corrales, F.J. (Fernando José)
Keywords: Methionine Adenosyltransferase/chemistry
Issue Date: 2002
Publisher: American Society for Biochemistry and Molecular Biology
Publisher version: http://www.jbc.org/content/277/14/12061
ISSN: 1083-351X
Citation: Sanchez del Pino MM, Perez-Mato I, Sanz JM, Mato JM, Corrales FJ. Folding of dimeric methionine adenosyltransferase III: identification of two folding intermediates. J Biol Chem 2002 Apr 5;277(14):12061-12066.
Abstract
Methionine adenosyl transferase (MAT) is an essential enzyme that synthesizes AdoMet. The liver-specific MAT isoform, MAT III, is a homodimer of a 43.7-kDa subunit that organizes in three nonsequential alpha-beta domains. Although MAT III structure has been recently resolved, little is known about its folding mechanism. Equilibrium unfolding and refolding of MAT III, and the monomeric mutant R265H, have been monitored using different physical parameters. Tryptophanyl fluorescence showed a three-state folding mechanism. The first unfolding step was a folding/association process as indicated by its dependence on protein concentration. The monomeric folding intermediate produced was the predominant species between 1.5 and 3 m urea. It had a relatively compact conformation with tryptophan residues and hydrophobic surfaces occluded from the solvent, although its N-terminal region may be very unstructured. The second unfolding step monitored the denaturation of the intermediate. Refolding of the intermediate showed first order kinetics, indicating the presence of a kinetic intermediate within the folding/association transition. Its presence was confirmed by measuring the 1,8-anilinonaphtalene-8-sulfonic acid binding in the presence of tripolyphosphate. We propose that the folding rate-limiting step is the formation of an intermediate, probably a structured monomer with exposed hydrophobic surfaces, that rapidly associates to form dimeric MAT III.
Permanent link: http://hdl.handle.net/10171/21567
Appears in Collections:DA - CIMA - Unidad de Proteómica, Genómica y Bioinformática - Artículos de revista
DA - CIMA - Terapia génica y Hepatología - Hepatología bioquímica - Artículos de revista

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