Sequence of an isoleucine tRNA from Mycoplasma mycoides sp. Capri. Astrid Schon. Department of Molecular Biophysics and Biochemistry, Yale University, ...
Volume 15 Number 13 1987
Nucleic Acids Research
Sequence of an isoleucine tRNA from Mycoplasma mycoides sp. Capri Astrid Schon Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA Submitted May 15, 1987 Accession no. Y00372
The t R N A s from Mycoplasma show an extremely low degree o f nucleotide modification. In particular, the organism lacks the uracil-tRNA methylase needed for the synthesis of ribothymidine (in position 54 o f normal tRNAs). T o date only three t R N A s have been sequenced from Mycoplasma strains ( 1 - 3 ) . As we are interested in nucleotide modification and codon recognition properties, and as there is I( evidence for a divergent genetic code in these tRNA GAU organisms ( 4 ) , I sequenced a tRNA 11 " from Mycoplasma previously isolated (5). The sequence was *OH determined by standard R N A sequencing methods % and the nucleotide composition confirmed by A P HPLC nucleotide analysis. G-c Besides a number of simple modified nucleoG- C tides, t R N A I U contains the complex modified * Z }J 6 base t A at position 37, which has been found in u-A all isoleucine t R N A s sequenced to date (6). In S4UA~U contrast to ribothymidine, which is dispensable c GA A for efficient translation ( 5 ) , some of the modi- G °
