Ribosomes are key macromolecular components involved in the synthesis of proteins. They are made up of proteins and ribosomal RNAs. The goal of this proposal is to map the relative positions of single-stranded regions of rRNA that occur on the ribosome, using short, complimentary oligomers as probes. Interactions will be analyzed by fluorescence anisotropy, energy transfer techniques and photoaffinity labeling. The distance of selected sites from various ribosomal proteins will be measured by neutron diffraction. These studies will provide valuable information on the detailed structure of the ribosome and ribosomal subunits, and thus enhance our understanding of the process of protein synthesis.