Abnormal Codon Recognition of Glycyl-tRNA from the Posterior Silk Glands of Bombyx mori1

Abstract

Two species of glycine tRNA (tRNA₁^Gly and tRNA₂^Gly were purified from the posterior silk glands of Bombyx mori. Digestion of tRNA₁^Gly with RNase Tl revealed that this tRNA corresponds to the species which has recently been sequenced by Garel and Keith (1), and Züňiga and Steitz (2), independently. However, the position 9 of our tRNA₁^Gly was occupied by unmodified guanosine instead of m¹G. The codon recognition properties of highly purified tRNA₁^Gly and tRNA₂^Gly were investigated in detail according to the method of Nirenberg and Leder (3). All four glycine codons were recognized by tRNA₁^Gly and by tRNA₂^Gly These results suggest the presence of abnormal base-pairs between the first base G of the anticodon and all the third bases of the codons, or the recognition by “two-out-of-three” type reading.