Interactions of Monovalent and Divalent Cations at Palmitoyl-Oleoyl-Phosphatidylcholine Interface.

Li is a biologically active and medically important cation. Experiments show that Li modulates some phospholipid bilayer properties in a manner similar to divalent cations, rather than other monovalent cations. We previously performed a comparative simulation study of the interaction of several monovalent cations with palmitoyl-oleoyl-phosphatidylcholine bilayers and reported that Li exhibited the highest association with lipids and formed a unique tetrahedral coordinated structure with lipid head groups.

Towards a Unified Understanding of Lithium Action in Basic Biology and its Significance for Applied Biology.

Lithium has literally been everywhere forever, since it is one of the three elements created in the Big Bang. Lithium concentration in rocks, soil, and fresh water is highly variable from place to place, and has varied widely in specific regions over evolutionary and geologic time. The biological effects of lithium are many and varied.

Molecular dynamics simulations of ether- and ester-linked phospholipids.

Dissimilarities in the bulk structure of bilayers composed of ether- vs ester-linked lipids are well-established; however, the atomistic interactions responsible for these differences are not well known. These differences are important in understanding of why archaea have a different bilayer composition than the other domains of life and why humans have larger concentrations of plasmalogens in specialized membranes? In this paper, we simulate two lipid bilayers, the ester linked dipalmitoylphosphatidylcholine (DPPC) and the ether lined dihexadecylphosphatidylcholine (DHPC), to study these variations. The structural analysis of the bilayers reveals that DPPC is more compressible than DHPC.

Effects of Lithium and Other Monovalent Ions on Palmitoyl Oleoyl Phosphatidylcholine Bilayer.

Interactions of monovalent salts with lipid membranes are explored with molecular dynamics (MD) simulations. The simulations included the monovalent ions Na and K, for their importance in physiology, Li for its small size and importance in several medical conditions including bipolar disorder, and Rb for its large size. All simulations included Cl as counterions.

The effect of cross-link distributions in axially-ordered, cross-linked networks.

Cross-linking between the constituent chains of biopolymers has a marked effect on their materials' properties. In certain of these materials, such as fibrillar collagen, increases in cross-linking lead to an increase in the melting temperature. Fibrillar collagen is an axially-ordered network of cross-linked polymer chains exhibiting a broadened denaturation transition, which has been explained in terms of the successive denaturation with temperature of multiple species.