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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Methylene Blue Location in (Hydroperoxized) Cardiolipin Monolayer: Implication in Membrane Photodegradation

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Autor(es):
de Souza, R. M. ; Siani, P. ; Schmidt, T. F. ; Itri, R. ; Dias, L. G.
Número total de Autores: 5
Tipo de documento: Artigo Científico
Fonte: Journal of Physical Chemistry B; v. 121, n. 36, p. 8512-8522, SEP 14 2017.
Citações Web of Science: 1
Resumo

We present molecular dynamics simulations of cardiolipin (CL) and CL monohydroperoxized derivative (CLOOH) monolayers to investigate the initial steps of phospholipid oxidation induced by methylene blue (MB) photoexcitation under continuous illumination. We considered different MB atomic charge distributions to simulate the MB electronic distribution in the singlet ground and triplet excited states. Simulation results allied to experimental data revealed that initial CL photooxidation probably occurs via a type II mechanism, to produce lipid hydroperoxide by singlet oxygen attack to the alkyl chain unsaturations. The resulting hydroperoxide group prefers to reside near the aqueous interface, to increase the membrane surface area and to decrease lipid packing. Interestingly, MB orientation changes from nearly parallel to the water-monolayer interface in the ground state to normal to the interface in its triplet excited state. The latter orientation favors oxidative chain reaction continuity via a type I mechanism, during which the hydrogen atom must be transferred from the hydroperoxide group to triplet MB. Taken together, the present results can be extrapolated to improve our understanding of how oxidation progresses in lipidic biomembrane, which will lead to the formation of oxidized species with shortened chains and will cause severe photodamage to self-organized systems. (AU)

Processo FAPESP: 13/08166-5 - Química em interfaces: interações de fármacos, peptídios e enzimas com membranas modelos
Beneficiário:Iolanda Midea Cuccovia
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 08/07240-9 - Monocamadas e bicamadas lipídicas: adsorção de azul de metileno e fotossensibilização
Beneficiário:Thaís Fernandes Schmidt
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 12/50680-5 - Fotossensibilização nas ciências da vida
Beneficiário:Mauricio da Silva Baptista
Linha de fomento: Auxílio à Pesquisa - Temático