Not Only Oxidation of Cardiolipin Affects the Affinity of Cytochrome c for Lipid Bilayers

Autor(es)

Kawai, Cintia ^{[1, 2]} ; Ferreira, Juliana C. ^[3] ; Baptista, Mauricio S. ^[2] ; Nantes, Iseli L. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210580 Santo Andre, SP - Brazil

^[2] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-05508900 Sao Paulo - Brazil

^[3] Univ Fed Sao Paulo, Dept Biofis, BR-04021001 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry B; v. 118, n. 41, p. 11863-11872, OCT 16 2014.
• Citações Web of Science: 10

Resumo

Fluorescence quenching of lipid-bound pyrene was used to assess the binding of cytochrome c (cyt c) to liposomes that mimic the inner mitochondrial membrane (IMM) POPC/DOPE/TOCL, with the conditions that it did or did not contain oxidized phosphatidylcholine molecules, i.e., 1-O-hexadecyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC), or a mixture of two hydroperoxide isomers derived from POPC (POPCOX). The binding isotherms reveal two dissociation constants, KD(1) and KD(2), representing, respectively, the low- and high-affinity states of the membrane. These dissociation constants probably are due to the lipid reorganization promoted by cyt c, as observed in giant unilamellar vesicles that contain fluorescent cardiolipin (CL). The presence of PazePC, which has a nonreactive carboxylic group, increased the KD(1) and KD(2) values 1.2- and 4.5-fold, respectively. The presence of POPCOX which has a reactive peroxide group, decreased the KD(1) value 1.5-fold, increased the KD(2) value 10-fold, and significantly reduced the salt-induced detachment of cyt c. MALDI-TOF spectrometry analysis of cyt c incubated with liposomes containing POPCox demonstrated a mass increase corresponding to the formation of nonenal adducts as hydrophobic anchors. Electronic absorption spectroscopy, circular dichroism, and magnetic circular dichroism demonstrated that all of the lipids studied promoted changes in the cyt c coordination sphere. Therefore, in the presence of CL, the oxidation of zwitterionic lipids also promotes changes in the cyt c structure and in the affinity for lipid bilayers. (AU)

• Processo FAPESP: 12/12663-1 - Oxigênio singlete e peróxidos em química biológica
• Beneficiário: Paolo Di Mascio
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 12/07456-7 - Estudos por citometria de fluxo de mecanismos de morte e proteção celular promovida por compostos porfirinóides, fenotiazinas e teluranas associadas a nanoestruturas: montagem de uma sala multiusuário de biologia celular
• Beneficiário: Iseli Lourenço Nantes Cardoso
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/07937-8 - Redoxoma
• Beneficiário: Ohara Augusto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 12/50680-5 - Fotossensibilização nas ciências da vida
• Beneficiário: Mauricio da Silva Baptista
• Modalidade de apoio: Auxílio à Pesquisa - Temático