A structural investigation by Nuclear Magnetic Resonance (NMR) spectroscopy of RNA-protein interactions will be carried out. These interactions are poorly understood, and their importance in areas such as RNA processing and RNA viruses is rapidly becoming appreciated. The systems to be studied include the prokaryotic ribosome, the eukaryotic spliceosome and the regulation of transcription in bacteriophage T4. In the ribosome and spliceosome, specific RNA-protein interactions are crucial to structure and function, and components of each including individual proteins, RNA fragments and complexes will be isolated and studied. In addition, the structure of the putative DNA- binding domain of a vital protein that controls transcription in bacteriophage T4 will be determined. %%% Interactions between proteins and nucleic acids are central to many cellular processes and the results of this research will provide important insights into the mechanisms by which proteins recognize specific nucleic acid sequences.