TY - JOUR
T1 - Topography of tyrosine residues and their involvement in peroxidation of polyunsaturated cardiolipin in cytochrome c/cardiolipin peroxidase complexes
AU - Kapralov, Alexandr A.
AU - Yanamala, Naveena
AU - Tyurina, Yulia Y.
AU - Castro, Laura
AU - Samhan-Arias, Alejandro
AU - Vladimirov, Yuri A.
AU - Maeda, Akihiro
AU - Weitz, Andrew A.
AU - Peterson, Jim
AU - Mylnikov, Danila
AU - Demicheli, Verónica
AU - Tortora, Verónica
AU - Klein-Seetharaman, Judith
AU - Radi, Rafael
AU - Kagan, Valerian E.
N1 - Funding Information:
This study was supported by NIH : HL70755 , HL094488 ; U19 AIO68021 ; by NIOSH OH008282 , Grant RFFI 08-04-01074-a . This work was supported by grants from Agencia Nacional de investigación e Innovación (ANII), Uruguay, to VD (FCE2009_2562), LC (FCE2007_398) and RR (FCE2009_2486) and grants by the Howard Hughes Medical Institute and Comisión Sectorial de Investigación Científica (CSIC), Universidad de la República, Uruguay, to RR. VD and VT were partially supported by fellowships from Programa de Desarrollo de Ciencias Básicas (PEDECIBA), Uruguay, and Agencia Nacional de Investigación e Innovación. RR is a Howard Hughes International Research Scholar. AKSA is a recipient of a research fellowship from La Junta de Extremadura y el Fondo Social Europeo (2010063090).
PY - 2011/9
Y1 - 2011/9
N2 - Formation of cytochrome c (cyt c)/cardiolipin (CL) peroxidase complex selective toward peroxidation of polyunsaturated CLs is a pre-requisite for mitochondrial membrane permeabilization. Tyrosine residues - via the generation of tyrosyl radicals (Tyr) - are likely reactive intermediates of the peroxidase cycle leading to CL peroxidation. We used mutants of horse heart cyt c in which each of the four Tyr residues was substituted for Phe and assessed their contribution to the peroxidase catalysis. Tyr67Phe mutation was associated with a partial loss of the oxygenase function of the cyt c/CL complex and the lowest concentration of H2O2-induced Tyr radicals in electron paramagnetic resonance (EPR) spectra. Our MS experiments directly demonstrated decreased production of CL-hydroperoxides (CL-OOH) by Tyr67Phe mutant. Similarly, oxidation of a phenolic substrate, Amplex Red, was affected to a greater extent in Tyr67Phe than in three other mutants. Tyr67Phe mutant exerted high resistance to H2O2-induced oligomerization. Measurements of Tyr fluorescence, hetero-nuclear magnetic resonance (NMR) and computer simulations position Tyr67 in close proximity to the porphyrin ring heme iron and one of the two axial heme-iron ligand residues, Met80. Thus, the highly conserved Tyr67 is a likely electron-donor (radical acceptor) in the oxygenase half-reaction of the cyt c/CL peroxidase complex.
AB - Formation of cytochrome c (cyt c)/cardiolipin (CL) peroxidase complex selective toward peroxidation of polyunsaturated CLs is a pre-requisite for mitochondrial membrane permeabilization. Tyrosine residues - via the generation of tyrosyl radicals (Tyr) - are likely reactive intermediates of the peroxidase cycle leading to CL peroxidation. We used mutants of horse heart cyt c in which each of the four Tyr residues was substituted for Phe and assessed their contribution to the peroxidase catalysis. Tyr67Phe mutation was associated with a partial loss of the oxygenase function of the cyt c/CL complex and the lowest concentration of H2O2-induced Tyr radicals in electron paramagnetic resonance (EPR) spectra. Our MS experiments directly demonstrated decreased production of CL-hydroperoxides (CL-OOH) by Tyr67Phe mutant. Similarly, oxidation of a phenolic substrate, Amplex Red, was affected to a greater extent in Tyr67Phe than in three other mutants. Tyr67Phe mutant exerted high resistance to H2O2-induced oligomerization. Measurements of Tyr fluorescence, hetero-nuclear magnetic resonance (NMR) and computer simulations position Tyr67 in close proximity to the porphyrin ring heme iron and one of the two axial heme-iron ligand residues, Met80. Thus, the highly conserved Tyr67 is a likely electron-donor (radical acceptor) in the oxygenase half-reaction of the cyt c/CL peroxidase complex.
KW - Cardiolipin
KW - Cardiolipin hydroperoxide
KW - Cytochrome c
KW - Peroxidase
KW - Tyrosine
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U2 - 10.1016/j.bbamem.2011.04.009
DO - 10.1016/j.bbamem.2011.04.009
M3 - Article
C2 - 21550335
AN - SCOPUS:79959958733
SN - 0005-2736
VL - 1808
SP - 2147
EP - 2155
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
IS - 9
ER -