PHOTOCHEMICALLY INDUCED TRANSITION OF 4-THIOURIDINE TO URIDINE OR URIDINE AND CYTIDINE IN E COLI TRANSFER RIBONUCLEIC ACID

Little is known about the contribution of the minor nucleotides to the functional properties of tRNA. Although impressive progress has been made for the chemical synthesis of the gene for alanine tRNA from yeast(Kumar et al., 1968) the total synthesis of a tRNA containing the minor bases is not expected in the near future. The selective chemical modification of specific minor components in tRNA provides an approach for the study of the functional role of the minor nucleotides avoiding de novo synthesis of tRNA. Modification of a minor but not of a major component allows the alteration of topographically well-defined regions for tRNA species with known primary structure. A novel reaction is described in this paper which selectively transforms the minor nucleoside 4-thiouridine to uridine or uridine and cytidine in E. coli tRNA under extremely mild photochemical conditions. © 1969.