Biological Membrane Structure, II. A Detailed Model for the Retinal Rod Outer Segment Membrane

Abstract

A model, based on the available chemical, electron microscopic, and x-ray diffraction data, has been developed for the structure of the retinal rod outer segment membranes. The model consists of a double layer of globular protein molecules, with lipid bilayer filling the spaces between the proteins. The electron density across the membrane has been calculated and shown to be in agreement with that found by x-ray diffraction. The protein molecules "float" half submerged in a lipid field; this serves to orient them in the same way at all times relative to incident radiation in the intact retina.