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

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

Author de Souza, R. M. Google Scholar
Siani, P. Google Scholar
Schmidt, T. F. Autor UNIFESP Google Scholar
Itri, R. Google Scholar
Dias, L. G. Google Scholar
Abstract 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.
xmlui.dri2xhtml.METS-1.0.item-coverage Washington
Language English
Sponsor CNPq Brazilian agency
FAPESP Brazilian agency
CNPq research fellowship
Grant number FAPESP: 2012/50680-5
CAPES: 7119-12-7
FAPESP: 2013/08166-5
FAPESP: 2008/07240-9
Date 2017
Published in Journal Of Physical Chemistry B. Washington, v. 121, n. 36, p. 8512-8522, 2017.
ISSN 1520-6106 (Sherpa/Romeo, impact factor)
Publisher Amer Chemical Soc
Extent 8512-8522
Access rights Closed access
Type Article
Web of Science ID WOS:000411171900009

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