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-Structure paper
Title | Structural basis of successive adenosine modifications by the conserved ribosomal methyltransferase KsgA. |
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Journal, issue, pages | Nucleic Acids Res, Vol. 49, Issue 11, Page 6389-6398, Year 2021 |
Publish date | Jun 21, 2021 |
Authors | Niklas C Stephan / Anne B Ries / Daniel Boehringer / Nenad Ban / |
PubMed Abstract | Biogenesis of ribosomal subunits involves enzymatic modifications of rRNA that fine-tune functionally important regions. The universally conserved prokaryotic dimethyltransferase KsgA sequentially ...Biogenesis of ribosomal subunits involves enzymatic modifications of rRNA that fine-tune functionally important regions. The universally conserved prokaryotic dimethyltransferase KsgA sequentially modifies two universally conserved adenosine residues in helix 45 of the small ribosomal subunit rRNA, which is in proximity of the decoding site. Here we present the cryo-EM structure of Escherichia coli KsgA bound to an E. coli 30S at a resolution of 3.1 Å. The high-resolution structure reveals how KsgA recognizes immature rRNA and binds helix 45 in a conformation where one of the substrate nucleotides is flipped-out into the active site. We suggest that successive processing of two adjacent nucleotides involves base-flipping of the rRNA, which allows modification of the second substrate nucleotide without dissociation of the enzyme. Since KsgA is homologous to the essential eukaryotic methyltransferase Dim1 involved in 40S maturation, these results have also implications for understanding eukaryotic ribosome maturation. |
External links | Nucleic Acids Res / PubMed:34086932 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.1 Å |
Structure data | EMDB-12736, PDB-7o5h: |
Chemicals | ChemComp-MG: |
Source |
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Keywords | RIBOSOME / Methyltransferase KsgA / 30S |