4adv

Structure of the E. coli methyltransferase KsgA bound to the E. coli 30S ribosomal subunitStructure of the E. coli methyltransferase KsgA bound to the E. coli 30S ribosomal subunit

4adv, resolution 13.50Å Show:Asymmetric Unit Biological Assembly Structural highlights 4adv is a 10 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 13.5Å Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RS2_ECOLI Publication Abstract from PubMed The assembly of the ribosomal subunits is facilitated by ribosome biogenesis factors. The universally conserved methyltransferase KsgA modifies two adjacent adenosine residues in the 3'-terminal helix 45 of the 16 S ribosomal RNA (rRNA). KsgA recognizes its substrate adenosine residues only in the context of a near mature 30S subunit and is required for the efficient processing of the rRNA termini during ribosome biogenesis. Here, we present the cryo-EM structure of KsgA bound to a nonmethylated 30S ribosomal subunit. The structure reveals that KsgA binds to the 30S platform with the catalytic N-terminal domain interacting with substrate adenosine residues in helix 45 and the C-terminal domain making extensive contacts to helix 27 and helix 24. KsgA excludes the penultimate rRNA helix 44 from adopting its position in the mature 30S subunit, blocking the formation of the decoding site and subunit joining. We suggest that the activation of methyltransferase activity and subsequent dissociation of KsgA control conformational changes in helix 44 required for final rRNA processing and translation initiation. Structural Insights into Methyltransferase KsgA Function in 30S Ribosomal Subunit Biogenesis.,Boehringer D, O'Farrell HC, Rife JP, Ban N J Biol Chem. 2012 Mar 23;287(13):10453-9. Epub 2012 Feb 3. PMID:22308031 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Adenosine dimethyltransferase 3D structures Ribosome 3D structures