Identity elements of Saccharomyces cerevisiae tRNAHis

Abstract

Recognition of tRNAHis by Saccharomyces corevisiae histidyl-tRNA synthetase was studied using in vitro transcripts. Histidine tRNA is unique in possessing an extra nucleotide, G1, at the 5′ end. Mutation studies indicate that this irregular secondary structure at the end of the acceptor stem is important for aminoacylation with histidine, while the requirement of either base of this extra base pair is smaiier than that in Escherichia coli. The anticodon was also found to be required for histidylation. The regions involved in histidyiation are essentially the same as those in E.coli, whereas the proportion of the contributions of the two portions distant from each other, the anticodon and the end of the acceptor stem, makes a substantial difference between the two systems. © 1995 Oxford University Press.