Influence of Fe2+ on lipid orientation in the cell membrane bilayer: Quantum chemical modelling
Abstract
To understand the dynamics of hole formation and the progression of hole closure in the membrane layer at the molecular level, the structures of phospholipids and iron-ion associates were modelled using quantum-mechanical methods. It has been found that metal ion fixation to the lipid chain is insignificant in forming lipid conformational movement. Similarly, metal ion fixation in the case of the –N(CH3)3 head in the lipid head group is not formed. The iron ion binds two lipid molecules in the orthophosphoric region, forming an energetically stable bridge between orthophosphoric fragments. As a result of this process, the lipid aliphatic chains change their conformation: a curved chain forms around the metal ion centre from a straight structure. A typical molecular charge redistribution during excitation was determined and described. It is stated that, due to the energetically favourable position of the Fe2+ ion, one lipid serves as a charge donor and the other as a charge acceptor.
