Abstract
The intracellular ribosome crystals from chick embryos incubated at 5 degrees C have been isolated; stable products of their dissociation were shown to include single ribosomes, tetramers of ribosomes, and tetramers of large subunits. Conditions were found for the formation in vitro not only of the p4 crystals from ribosomal tetramers but also of the tetramers themselves from free ribosomes. The polypeptide synthesizing activity of these ribosomes was found to be unimpaired by their constraint in the tetrameric configuration.