X-ray scattering studies of heavy atom bound erythrocyte membrane suspensions

We have observed a periodic intensity variation of scattered x-rays from uranyl labeled erythrocyte membranes. Using unique x-ray scattering methods, we have made these measurements from membrane suspensions in which the vesicles appear, by phase contrast microscopy, to be normal in shape. The periodic intensity variation is not present for membranes labeled on one side only. The frequency of the variation permits calculation of membrane width, which we find to be 55Å.