The gene encodes RlmQ, the 23S rRNA methyltransferase forming mG2574 in the A-site of the peptidyl transferase center.

Ribosomal RNA contains many posttranscriptionally modified nucleosides, particularly in the functional parts of the ribosome. The distribution of these modifications varies from one organism to another. In , the model organism for Gram-positive bacteria, mass spectrometry experiments revealed the presence of 7-methylguanosine (mG) at position 2574 of the 23S rRNA, which lies in the A-site of the peptidyl transferase center of the large ribosomal subunit.

Identification of U47 in three thermophilic archaea, one mesophilic archaeon, and one hyperthermophilic bacterium.

Analysis of the profile of the tRNA modifications in several allowed us to observe a novel modified uridine in the V-loop of several tRNAs from two species: and Recently, Ohira and colleagues characterized 2'-phosphouridine (U) at position 47 in tRNAs of thermophilic , as well as in several other archaea and thermophilic bacteria. From the presence of the gene corresponding to the RNA kinase responsible for U47 formation, they also concluded that U47 should be present in tRNAs of other thermophilic Reanalysis of our earlier data confirms that the unidentified residue in tRNAs of both and is indeed 2'-phosphouridine followed by mC48. Moreover, we find this modification in several tRNAs of other and of the hyperthermophilic bacterium .

The open reading frame encodes the SPOUT methyltransferase RlmP forming 2'--methylguanosine at position 2553 in the A-loop of 23S rRNA.

A previous bioinformatic analysis predicted that the open reading frame of encodes an RNA methyltransferase of the SPOUT superfamily. Here we show that YsgA is the 2'--methyltransferase that targets position G2553 ( numbering) of the A-loop of 23S rRNA. This was shown by a combination of biochemical and mass spectrometry approaches using both rRNA extracted from wild-type or cells and in vitro synthesized rRNA.

Post-Transcriptional Modifications of Conserved Nucleotides in the T-Loop of tRNA: A Tale of Functional Convergent Evolution.

The high conservation of nucleotides of the T-loop, including their chemical identity, are hallmarks of tRNAs from organisms belonging to the three Domains of Life. These structural characteristics allow the T-loop to adopt a peculiar intraloop conformation able to interact specifically with other conserved residues of the D-loop, which ultimately folds the mature tRNA in a unique functional canonical L-shaped architecture. Paradoxically, despite the high conservation of modified nucleotides in the T-loop, enzymes catalyzing their formation depend mostly on the considered organism, attesting for an independent but convergent evolution of the post-transcriptional modification processes.