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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Reactive oxygen species at phospholipid bilayers: Distribution, mobility and permeation

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Cordeiro, Rodrigo M. [1]
Total Authors: 1
[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210170 Santo Andre, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES; v. 1838, n. 1, B, p. 438-444, JAN 2014.
Web of Science Citations: 76

Reactive oxygen species (ROS) are involved in biochemical processes such as redox signaling, aging, carcinogenesis and neurodegeneration. Although biomembranes are targets for reactive oxygen species attack, little is known about the role of their specific interactions. Here, molecular dynamics simulations were employed to determine the distribution, mobility and residence times of various reactive oxygen species at the membrane-water interface. Simulations showed that molecular oxygen (O-2) accumulated at the membrane interior. The applicability of this result to singlet oxygen (O-2(-)) was discussed. Conversely, superoxide (Cc) radicals and hydrogen peroxide (H2O2) remained at the aqueous phase. Both hydroxyl (HO) and hydroperoxyl (HO2) radicals were able to penetrate deep into the lipid headgroups region. Due to membrane fluidity and disorder, these radicals had access to potential peroxidation sites along the lipid hydrocarbon chains, without having to overcome the permeation free energy barrier. Strikingly, HO2 radicals were an order of magnitude more concentrated in the headgroups region than in water, implying a large shift in the acid-base equilibrium between HO2 and O. In comparison with O-2, both HO and HO2 radicals had lower lateral mobility at the membrane. Simulations revealed that there were intermittent interruptions in the H-bond network around the HO radicals at the headgroups region. This effect is expected to be unfavorable for the H-transfer mechanism involved in HO diffusion. The implications for lipid peroxidation and for the effectiveness of membrane antioxidants were evaluated. (C) 2013 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 12/50680-5 - Photosensitization in life sciences
Grantee:Mauricio da Silva Baptista
Support type: Research Projects - Thematic Grants