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- Enzymes (1)
- METTL8 (1)
- Mitochondrial Matrix Protein (1)
- Modified Nucleotides in tRNAs (1)
- N6-methyladenosine (m6A) (1)
- Organelles (1)
- RNA (1)
- RNA Methyltransferase (1)
- YTH reader proteins (1)
- atomic mutagenesis (1)
- demethylase enzymes FTO and ALKBH5 (1)
- modified nucleosides (1)
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- Institut für Organische Chemie (2) (remove)
Sonstige beteiligte Institutionen
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells, Göttingen (1)
- Department of Cellular Biochemistry, University Medical Centre Göttingen (1)
- Department of Molecular Biology, University Medical Centre Göttingen (1)
- Department of Molecular Biology, University Medical Centre Göttingen, Göttingen 37073, Germany (1)
- Göttingen Center for Molecular Biosciences, Georg- August University Göttingen, Göttingen 37077, Germany (1)
- Göttingen Center for Molecular Biosciences, University of Göttingen (1)
EU-Project number / Contract (GA) number
- 682586 (1)
N\(^6\)-methyladenosine (m\(^6\)A) is an important modified nucleoside in cellular RNA associated with multiple cellular processes and is implicated in diseases. The enzymes associated with the dynamic installation and removal of m\(^6\)A are heavily investigated targets for drug research, which requires detailed knowledge of the recognition modes of m\(^6\)A by proteins. Here, we use atomic mutagenesis of m\(^6\)A to systematically investigate the mechanisms of the two human m\(^6\)A demethylase enzymes FTO and ALKBH5 and the binding modes of YTH reader proteins YTHDF2/DC1/DC2. Atomic mutagenesis refers to atom-specific changes that are introduced by chemical synthesis, such as the replacement of nitrogen by carbon atoms. Synthetic RNA oligonucleotides containing site-specifically incorporated 1-deaza-, 3-deaza-, and 7-deaza-m\(^6\)A nucleosides were prepared by solid-phase synthesis and their RNA binding and demethylation by recombinant proteins were evaluated. We found distinct differences in substrate recognition and transformation and revealed structural preferences for the enzymatic activity. The deaza m\(^6\)A analogues introduced in this work will be useful probes for other proteins in m\(^6\)A research.
Modified nucleotides in tRNAs are important determinants of folding, structure and function. Here we identify METTL8 as a mitochondrial matrix protein and active RNA methyltransferase responsible for installing m\(^3\)C\(_{32}\) in the human mitochondrial (mt-)tRNA\(^{Thr}\) and mt-tRNA\(^{Ser(UCN)}\). METTL8 crosslinks to the anticodon stem loop (ASL) of many mt-tRNAs in cells, raising the question of how methylation target specificity is achieved. Dissection of mttRNA recognition elements revealed U\(_{34}\)G\(_{35}\) and t\(^6\)A\(_{37}\)/(ms\(^2\))i\(^6\)A\(_{37}\), present concomitantly only in the ASLs of the two substrate mt-tRNAs, as key determinants for METTL8-mediated methylation of C\(_{32}\). Several lines of evidence demonstrate the influence of U\(_{34}\), G\(_{35}\), and the m\(^3\)C\(_{32}\) and t\(^6\)A\(_{37}\)/(ms\(^2\))i\(^6\)A\(_{37}\) modifications in mt-tRNA\(^{Thr/Ser(UCN)}\) on the structure of these mt-tRNAs. Although mt-tRNA\(^{Thr/Ser(UCN)}\) lacking METTL8-mediated m\(^3\)C\(_{32}\) are efficiently aminoacylated and associate with mitochondrial ribosomes, mitochondrial translation is mildly impaired by lack of METTL8. Together these results define the cellular targets of METTL8 and shed new light on the role of m\(^3\)C\(_{32}\) within mt-tRNAs.