Effect of rubber pollutants 6PPD and 6PDQ on a complex membrane

Area of Science:

• Environmental chemistry
• Biochemistry
• Materials science

Background:

• 6PPD is a widely used antioxidant and antiozonant in rubber products.
• The reaction product of 6PPD, 6PDQ, is also formed and is toxic.
• Both 6PPD and 6PDQ are hydrophobic and can interact with biological membranes.

Purpose of the Study:

• To investigate the behavior of 6PPD and 6PDQ within a complex biomembrane using molecular dynamics.
• To understand how these molecules affect membrane structure and properties.

Main Methods:

• Molecular dynamics simulations were employed to model the interaction of 6PPD and 6PDQ with a biomembrane.
• The insertion depth, state (monomeric or aggregated), and interactions with membrane components were analyzed.

Main Results:

• Both 6PPD and 6PDQ spontaneously insert into the biomembrane in a monomeric state.
• These molecules increase the fluidity of the phospholipid bilayer.
• 6PPD and 6PDQ do not form hydrogen bonds with lipids and avoid cholesterol, suggesting unhindered movement within the membrane.

Conclusions:

• The spontaneous insertion of 6PPD and 6PDQ into biological membranes alters their physicochemical properties.
• This membrane perturbation may explain the observed toxicity of 6PPD and 6PDQ to living organisms.