The Crystallization of Ribosomal Proteins from the 50 S Subunit of the Escherichia coli and Bacillus stearothermophilus Ribosome*

Several individual intact ribosomal proteins purified from bacterial sources under mild conditions have been crystallized. A number of these are suitable candidates for three-dimensional structural studies b x-ray dif-fraction techniques. Data collection to 3 J resolution for one of these proteins is in progress. The process whereby polypeptide chains are manufactured on the ribosome is evidently both complex and universally important in biology. Although the various steps are well understood, it is clear that a complete understanding of the mechanisms involved awaits a detailed description of the ribosome structure at he molecular level. The success achieved in identifying function within the structures of many globular proteins, notably enzymes (1,2), encourages a similar approach to this more complex system