tRNA processing and quality control in bacteria

In this work, we report that the only exoribonuclease in M. genitalium, RNase R,
is able to generate mature 3'-ends. The aminoacyl-acceptor stem, CCA terminus and
discriminator residue plays an important role in stopping RNase R digestion at the mature
3'-end. Disruption of the stem causes partial or complete degradation of the pre-tRNA,
whereas extension of the stem results in the formation of a mature 3’-end. CC residues in
CCA terminus and A or G residues at discriminator position are the most preferred
residues for precise stopping of RNase R at mature 3’ end. The significance of this works
shows that M. genitalium RNase R generates mature tRNA in a single step by
recognizing features in the terminal domains of tRNA, a process requiring multiple
RNases in most bacteria.