TY - JOUR
T1 - The Dnmt2 RNA methyltransferase homolog of Geobacter sulfurreducens specifically methylates tRNA-Glu
AU - Shanmugam, Raghuvaran
AU - Aklujkar, Muktak
AU - Schäfer, Matthias
AU - Reinhardt, Richard
AU - Nickel, Olaf
AU - Reuter, Gunter
AU - Lovley, Derek R.
AU - Ehrenhofer-Murray, Ann
AU - Nellen, Wolfgang
AU - Ankri, Serge
AU - Helm, Mark
AU - Jurkowski, Tomasz P.
AU - Jeltsch, Albert
N1 - Funding Information: Deutsche Forschungsgemeinschaft (DFG) Research Group FOR1082 and Deutscher Akademischer Austauschdienst (DAAD). Funding for open access charge: DFG and University Stuttgart. Conflict of interest statement. None declared.
PY - 2014/6/2
Y1 - 2014/6/2
N2 - Dnmt2 enzymes are conserved in eukaryotes, where they methylate C38 of tRNA-Asp with high activity. Here, the activity of one of the very few prokaryotic Dnmt2 homologs from Geobacter species (GsDnmt2) was investigated. GsDnmt2 was observed to methylate tRNA-Asp from flies and mice. Unexpectedly, it had only a weak activity toward its matching Geobacter tRNA-Asp, but methylated Geobacter tRNA-Glu with good activity. In agreement with this result, we show that tRNA-Glu is methylated in Geobacter while the methylation is absent in tRNA-Asp. The activities of Dnmt2 enzymes from Homo sapiens, Drosophila melanogaster, Schizosaccharomyces pombe and Dictyostelium discoideum for methylation of the Geobacter tRNA-Asp and tRNA-Glu were determined showing that all these Dnmt2s preferentially methylate tRNA-Asp. Hence, the GsDnmt2 enzyme has a swapped transfer ribonucleic acid (tRNA) specificity. By comparing the different tRNAs, a characteristic sequence pattern was identified in the variable loop of all preferred tRNA substrates. An exchange of two nucleotides in the variable loop of murine tRNA-Asp converted it to the corresponding variable loop of tRNA-Glu and led to a strong reduction of GsDnmt2 activity. Interestingly, the same loss of activity was observed with human DNMT2, indicating that the variable loop functions as a specificity determinant in tRNA recognition of Dnmt2 enzymes.
AB - Dnmt2 enzymes are conserved in eukaryotes, where they methylate C38 of tRNA-Asp with high activity. Here, the activity of one of the very few prokaryotic Dnmt2 homologs from Geobacter species (GsDnmt2) was investigated. GsDnmt2 was observed to methylate tRNA-Asp from flies and mice. Unexpectedly, it had only a weak activity toward its matching Geobacter tRNA-Asp, but methylated Geobacter tRNA-Glu with good activity. In agreement with this result, we show that tRNA-Glu is methylated in Geobacter while the methylation is absent in tRNA-Asp. The activities of Dnmt2 enzymes from Homo sapiens, Drosophila melanogaster, Schizosaccharomyces pombe and Dictyostelium discoideum for methylation of the Geobacter tRNA-Asp and tRNA-Glu were determined showing that all these Dnmt2s preferentially methylate tRNA-Asp. Hence, the GsDnmt2 enzyme has a swapped transfer ribonucleic acid (tRNA) specificity. By comparing the different tRNAs, a characteristic sequence pattern was identified in the variable loop of all preferred tRNA substrates. An exchange of two nucleotides in the variable loop of murine tRNA-Asp converted it to the corresponding variable loop of tRNA-Glu and led to a strong reduction of GsDnmt2 activity. Interestingly, the same loss of activity was observed with human DNMT2, indicating that the variable loop functions as a specificity determinant in tRNA recognition of Dnmt2 enzymes.
UR - http://www.scopus.com/inward/record.url?scp=84903140945&partnerID=8YFLogxK
U2 - https://doi.org/10.1093/nar/gku256
DO - https://doi.org/10.1093/nar/gku256
M3 - مقالة
SN - 0305-1048
VL - 42
SP - 6487
EP - 6496
JO - Nucleic acids research
JF - Nucleic acids research
IS - 10
ER -