Non-bilayer Lipids and the Inner Mitochondrial Membrane

Abstract

In the last decade the fluid mosaic model (Singer and Nicholson 1972) of biological membranes has become generally accepted as it provided a rationale for many structural and functional features of membranes. More recently, however it has become increasingly clear that this model is incomplete for reasons relating to lipid composition as well as functional abilities of biological membranes. First, although the chemical variation in membrane lipids is enormous, it is surprising that most of them can be divided into only two groups on structural grounds: The lipids of the first group, including PC* and sphingomyelin, will organize themselves in bilayers when they are in the fully hydrated state (bilayer lipids).It is obvious that this property has greatly contributed to the bilayer concept of biological membranes.