Modification of the amino acid acceptor stem of E. coli tRNA fMet by ligation of chemically synthesized ribooligonucleotides

Abstract

The single-stranged region of the amino acid acceptor stem corresponding to the 3'-end of E. coli tRNA Met f was replaced by ligation of chemically synthesized ribooligonucleotides, in order to change the length of the single-stranded CCA terminus. The chemically synthesized ribooligomers, CCA, ACCA, AACCA and CAACCA, were ligated to nuclease-treated E. coli tRNA Met f, which lacked the ACCA sequence at the 3'-end. The methionine acceptor activities of these modified tRNAs were examined using E. coli methionyl-tRNA synthetase. Ligation of the chemically synthesized pentamer (AACCA) to the acceptor terminus restored the methionine acceptor activity, whereas ligation of the hexamer (CAACCA) or trimer (CCA) to the acceptor terminus did not Modification of the acceptor terminus had no effect on the formylation of accepted methionine.