Plant Membrane Lipids

Abstract

This review discusses the 2 types of lipid protein membranes: the ionically-bound "unit membrane" type which resembles structures found in myelin figures and forms most readily with basic proteins; and the "corpuscular lipoprotein" membrane which results from hydrophobic binding of lipid hydrocarbon chains by hydrophobic regions of certain proteins. Electron microscopy has, so far, failed to discriminate between the 2 directions of lipid orientation. Recognition of the membrane lipids and their characteristic chemical and metabolic reactivities should develop discernment in this important frontier. The structure of the original organism probably resulted from physical forces which concentrate surface active substances. Whether its membranes guided construction and conformation of its macromolecular components is not known; the converse may have occurred. A similar but more approachable problem is presented by the developing membranes of cells. Does the protein structure guide adsorption of the surfactant lipids or do the lipids direct orientation and conformation of the protein? The plant cell possesses many attributes which will contribute to the answer of this pressing problem in biology. There is a bibliography with 102 references.