ATP and Mg2+ promote the reversible oligomerization and aggregation of chloroplast 2-Cys peroxiredoxin

• Autores: Aran, M.; Ferrero, D.; Wolosiuk, A.; Mora-García, S.; Wolosiuk, R.A.
• Año de publicación: 2011
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: J. Biol. Chem. 2011;286(26):23441-23451
• Materia: 2 ,2 ,2-trifluoroethanol; Antioxidant defense; Chaperone activity; Conserved residues; Cosolvents; Cysteine residues; Decamers; Functional changes; Helical conformation; Higher order; In-line; Low-to-high; Molecular chaperones; Native conformation; Non-covalent interaction; Peroxiredoxins; Post-translational modifications; Quaternary structure; Redox transformations; Self-polymerization; Amino acids; Chlorophyll; Conformations; Dichroism; Ethanol; Hydrogen peroxide; Oligomerization; Polymerization; Spheres; Transmission electron microscopy; Oligomers; 2 cysteine peroxiredoxin; adenosine triphosphate; arginine; cysteine; magnesium ion; peroxiredoxin; trifluoroethanol; unclassified drug; magnesium; peroxiredoxin; recombinant protein; vegetable protein; alpha helix; article; beta sheet; cell energy; chloroplast; circular dichroism; controlled study; enzyme activity; enzyme regulation; molecular interaction; molecular weight; nonhuman; oligomerization; oxidation reduction reaction; particle size; photochemistry; priority journal; protein aggregation; protein analysis; protein conformation; protein function; protein polymerization; protein processing; protein quaternary structure; rapeseed; surface plasmon resonance; transmission electron microscopy; chemistry; chloroplast; enzymology; genetics; metabolism; protein multimerization; protein secondary structure; Adenosine Triphosphate; Chloroplasts; Circular Dichroism; Magnesium; Peroxiredoxins; Plant Proteins; Protein Multimerization; Protein Structure, Quaternary; Protein Structure, Secondary; Recombinant Proteins
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

2-Cys peroxiredoxins (2-Cys Prxs) are ubiquitous peroxidases with important roles in cellular antioxidant defense and hydrogen peroxide-mediated signaling. Post-translational modifications of conserved cysteines cause the transition from low to high molecular weight oligomers, triggering the functional change from peroxidase to molecular chaperone. However, it remains unclear how non-covalent interactions of 2-Cys Prx with metabolites modulate the quaternary structure. Here, we disclose that ATP and Mg2+ (ATP/Mg) promote the self-polymerization of chloroplast 2-Cys Prx (polypeptide 23.5 kDa) into soluble higher order assemblies (>2 MDa) that proceed to insoluble aggregates beyond 5mMATP. Remarkably, the withdrawal of ATP or Mg2+ brings soluble oligomers and insoluble aggregates back to the native conformation without compromising the associated functions. As confirmed by transmission electron microscopy, ATP/Mg drive the toroid-like decamers (diameter 13 nm) to the formation of large sphere-like particles (diameter ∼30 nm). Circular dichroism studies on ATP-labeled 2-Cys Prx reveal that ATP/Mg enhance the proportion of β-sheets with the concurrent decrease in the content of α-helices. In line with this observation, the formation of insoluble aggregates is strongly prevented by 2,2,2-trifluoroethanol, a cosolvent employed to induce α-helical conformations. We further find that the response of self-polymerization to ATP/Mg departs abruptly from that of the associated peroxidase and chaperone activities when two highly conserved residues, Arg129 and Arg152, are mutated. Collectively, our data uncover that non-covalent interactions of ATP/Mg with 2-Cys Prx modulate dynamically the quaternary structure, thereby coupling the non-redox chemistry of cell energy with redox transformations at cysteine residues. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.
Fil:Aran, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Mora-García, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Wolosiuk, R.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.