Search results for "TRNA Methyltransferase"
showing 6 items of 16 documents
RNA nucleotide methylation
2011
Methylation of RNA occurs at a variety of atoms, nucleotides, sequences and tertiary structures. Strongly related to other posttranscriptional modifications, methylation of different RNA species includes tRNA, rRNA, mRNA, tmRNA, snRNA, snoRNA, miRNA, and viral RNA. Different catalytic strategies are employed for RNA methylation by a variety of RNA-methyltransferases which fall into four superfamilies. This review outlines the different functions of methyl groups in RNA, including biophysical, biochemical and metabolic stabilization of RNA, quality control, resistance to antibiotics, mRNA reading frame maintenance, deciphering of normal and altered genetic code, selenocysteine incorporation,…
The Dnmt2 RNA methyltransferase homolog of Geobacter sulfurreducens specifically methylates tRNA-Glu
2014
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 …
Expanding the chemical scope of RNA:methyltransferases to site-specific alkynylation of RNA for click labeling.
2010
This work identifies the combination of enzymatic transfer and click labeling as an efficient method for the site-specific tagging of RNA molecules for biophysical studies. A double-activated analog of the ubiquitous co-substrate S-adenosyl-l-methionine was employed to enzymatically transfer a five carbon chain containing a terminal alkynyl moiety onto RNA. The tRNA:methyltransferase Trm1 transferred the extended alkynyl moiety to its natural target, the N2 of guanosine 26 in tRNA(Phe). LC/MS and LC/MS/MS techniques were used to detect and characterize the modified nucleoside as well as its cycloaddition product with a fluorescent azide. The latter resulted from a labeling reaction via Cu(I…
tRNA stabilization by modified nucleotides.
2010
Post-transcriptional ribonucleotide modification is a phenomenon best studied in tRNA, where it occurs most frequently and in great chemical diversity. This paper reviews the intrinsic network of modifications in the structural core of the tRNA, which governs structural flexibility and rigidity to fine-tune the molecule to peak performance and to regulate its steady-state level. Structural effects of RNA modifications range from nanometer-scale rearrangements to subtle restrictions of conformational space on the angstrom scale. Structural stabilization resulting from nucleotide modification results in increased thermal stability and translates into protection against unspecific degradation …
Functional characterization of the human tRNA methyltransferases TRMT10A and TRMT10B
2020
Abstract The TRM10 family of methyltransferases is responsible for the N1-methylation of purines at position 9 of tRNAs in Archaea and Eukarya. The human genome encodes three TRM10-type enzymes, of which only the mitochondrial TRMT10C was previously characterized in detail, whereas the functional significance of the two presumably nuclear enzymes TRMT10A and TRMT10B remained unexplained. Here we show that TRMT10A is m1G9-specific and methylates a subset of nuclear-encoded tRNAs, whilst TRMT10B is the first m1A9-specific tRNA methyltransferase found in eukaryotes and is responsible for the modification of a single nuclear-encoded tRNA. Furthermore, we show that the lack of G9 methylation cau…
Eukaryotic rRNA Modification by Yeast 5-Methylcytosine-Methyltransferases and Human Proliferation-Associated Antigen p120.
2015
International audience; Modified nucleotide 5-methylcytosine (m(5)C) is frequently present in various eukaryotic RNAs, including tRNAs, rRNAs and in other non-coding RNAs, as well as in mRNAs. RNA: m(5)C-methyltranferases (MTases) Nop2 from S. cerevisiae and human proliferation-associated nucleolar antigen p120 are both members of a protein family called Nop2/NSUN/NOL1. Protein p120 is well-known as a tumor marker which is over-expressed in various cancer tissues. Using a combination of RNA bisulfite sequencing and HPLC-MS/MS analysis, we demonstrated here that p120 displays an RNA:m(5)C-MTase activity, which restores m(5)C formation at position 2870 in domain V of 25S rRNA in a nop2 Delta …