The project focuses on involvement of transfer RNAs in the first step of protein synthesis, and in other cellular processes. Experiments are being conducted to determine the molecular bases of the specificity and strength of complex formation in the interactions between aminoacyl tRNA synthetases and tRNAs. Experiments are aimed at determining whether a transient covalent bond forms in such complexes. Also, the involvement of tRNAs in cellular regulatory mechanisms is being explored. Particular attention is directed at interactions of tRNA Tyr and tRNA His, from bacteria. Affinity chromatography and other procedures are being used.