Nucleic Acids Research, 1975, Vol. 2, No. 1 61-78
© 1975
Articles |
Formylatable methionine transfer RNA from Mycoplasma: purification and comparison of partial nucleotide sequences with those of other prokaryotic initiator tRNAs
*Chemistry Department, Birmingham University Birmingham B15 2TT, UK +Department of Biology, Massachusetts Institute of Technology Cambridge, Massachusetts 02139, USA
Received November 7, 1974.
The major species of the formylatable methionine tRNA from Mycoiplasma mycoides var capri has been purified. The 5'- and 3'- terminal sequences of the purified tRNA are pC-G-and C-A-A-C-C-AOH, respectively. Thus, this tRNA also contains the unique structural feature found in two other prokaryotic initiator tRNAs in that the first nucleotide at the 5'-end cannot form a Watson-Crick type of base-pair to the fifth nucleotide from the 3'-end. The Mycoplasma tRNA does not contain ribothymidine; however, a specific uridine residue in the sequence G-U-
-C-G- can be enzymatically methylated by E. coli extracts to yield G-T-
-C-G. Since ribothymidine is absent In crude tRNA from this strain of Mycoplasma, the absence of T is probably due to the lack of a U
T modifying enzyme.