The objective of this research is to elucidate the mechanisms responsible for RNA-protein interactions. More specifically, a set of proteins (Ribosomal Protein S1, Initiation Factor-3, Host Factor Protein, and Elongation Factor-Tu and Ts) will be examined which appear to function in the E. coli cell by binding to RNA as part of several cellular processes and which may associate with each other or be in close spatial proximity. The importance of RNA-protein-protein interactions will also be studied. The effect and mechanism of inhibition of aurintricarboxylic acid will also be considered. The use of physical chemical techniques will be emphasized in the elucidation of physical parameters which govern RNA-protein interactions and their inhibition by aurintricarboxylic acid. Chemical modification procedures will also be used. The conformational consequences of the interaction will be explored in detail for both partners. The techniques employed will include: UV spectroscopy, circular dichroism, fluorescence spectroscopy, nuclear magnetic resonance spectroscopy, and boundary sedimentation. These studies will allow detailed molecular insight to be made of RNA-protein interactions which can ultimately be employed as a basis for models of in vivo macromolecular function and mode of action.