Resorcinolic
lipids, or
resorcinols, are commonly found in plant membranes. They consist of a substituted
benzene ring forming the hydrophilic
lipid head, attached to an alkyl chain forming the hydrophobic tail. Experimental results show alternative effects of
resorcinols on
lipid membranes. Depending on whether they are added to
lipid solutions before or after the formation of the
liposomes, they either stabilize or destabilize these
liposomes. Here we use atomistic molecular dynamics simulations to elucidate the molecular nature of this dual effect. Systems composed of either one of three
resorcinol homologs, differing in the alkyl tail length, interacting with
dimyristoylphosphatidylcholine lipid bilayers were studied. It is shown that
resorcinols preincorporated into bilayers induce order within the
lipid acyl chains, decrease the hydration of the
lipid headgroups, and make the bilayers less permeable to water. In contrast, simulations in which the
resorcinols are incorporated from the aqueous
solution into a preformed
phospholipid bilayer induce local disruption, leading to either transient pore formation or even complete
rupture of the membrane. In line with the experimental data, our simulations thus demonstrate that
resorcinols can either disturb or stabilize the membrane structure, and offer a detailed view of the underlying molecular mechanism.