Recovery of tyrosine acceptor activity by combining 3'-half molecule with stepwise degradation products of 5'-half molecule obtained from tyrosine tRNA

The influence of elongation-factor-Tu . GTP and anticodon-anticodon interactions on the anticodon loop conformation of yeast tRNATyr

The interactions of yeast tRNATyr, spin-labelled at position i6A-37 next to the anticodon, with EF-Tu . GTP and with Escherichia coli tRNAVal (which has a complementary anticodon) have been studied. The immobilization of the spin label upon ternary complex formation shows a conformational change of the anticodon region, although this part of tRNATyr is not in direct contact with the protein, as indicated by RNase T1 digestion. Upon anticodon-anticodon interaction, no conformational change of the anticodon loop of tRNATyr was observed.

Reconstitution of chemically synthesized ribooligonucleotides with naturally occurring tRNA fragments

Chemically synthesized yeast tRNA terminal fragments were reconstituted with natural tRNA fragments which were obtained by partial digestion with RNase T1. The synthetic 3'-nonanucleotide (I) accepted alanine (3% with respect to the intact tRNA) when combined with a 4-fold excess of the natural 5'-quarter and the chemically synthesized hexanucleotide (II) stimulated the aminoacylation of the natural 3'-half molecule.

Structure and function of E. coli formylmethionyl tRNA. I. Effect of modification of pyrimidine residues on aminoacyl synthetase recognition

E. coli formylmethionyl tRNA (tRNA(fMet)) has been irradiated with ultraviolet light in the presence of Mg(2+) to the extent of 50 per cent inactivation of amino acid acceptance. Separation of active and inactive molecules after irradiation has shown that ultraviolet light modification of the uridine in the anticodon, the uridine in the small loop, the 4-thiouridine, and the pyrimidines in the double-stranded stem adjacent to the dihydrouridine loop has no effect on aminoacylation or transformylation. The ultraviolet light-induced inactivation of methionine acceptance by tRNA(fMet) is due almost entirely to modification of the cytidine residues in the 3'-terminal CCA-OH sequence.