Electron microscope and low-angle X-ray diffraction studies on outer segment membranes from the retina of the frog

Abstract

Ordered arrays of particles about 40 Å in diameter within the outer segment membranes of retinal receptor have been observed by electron microscopy, and low-angle X-ray diffraction studies are in agreement with this finding. Surface-on views of outer segment membranes negatively-stained with phospho-tuhgstate or fixed with permanganate show square arrays of particles with a non-polar core 40 Å in diameter. Light diffraction patterns of a mask of holes simulating electron micrographs showed first and second orders of a uniformly square array with a unit cell side of about 70 Å.