Ribosomes: A Common Structural Feature

Abstract
A reflection between 45 and 50 Å has been observed in x-ray diffraction patterns from ribosomes extracted from Escherichia coli, Drosophila larvae, rat liver, and rabbit reticulocytes. This spacing appears to correspond to a common substructural feature within the ribosomes. The intensity distribution is consistent with a model in which part of the RNA is in the form of four or five parallel double helices 45 to 50 Å apart.