6q56

Crystal structure of the B. subtilis M1A22 tRNA methyltransferase TrmK

spinqualitylabelsall models 6q56, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6q56 is a 4 chain structure with sequence from Bacillus subtilis subsp. subtilis str. 168. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: NI Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TRMK_BACSU Catalyzes the S-adenosyl-L-methionine-dependent formation of N(1)-methyladenine at position 22 (m1A22) in tRNA. Publication Abstract from PubMed 1-Methyladenosine (m1A) is a modified nucleoside found at positions 9, 14, 22 and 58 of tRNAs, which arises from the transfer of a methyl group onto the N1-atom of adenosine. The yqfN gene of Bacillus subtilis encodes the methyltransferase TrmK (BsTrmK) responsible for the formation of m1A22 in tRNA. Here, we show that BsTrmK displays a broad substrate specificity, and methylates seven out of eight tRNA isoacceptor families of B. subtilis bearing an A22. In addition to a non-Watson-Crick base-pair between the target A22 and a purine at position 13, the formation of m1A22 by BsTrmK requires a full-length tRNA with intact tRNA elbow and anticodon stem. We solved the crystal structure of BsTrmK showing an N-terminal catalytic domain harbouring the typical Rossmann-like fold of Class-I methyltransferases and a C-terminal coiled-coil domain. We used NMR chemical shift mapping to drive the docking of BstRNASer to BsTrmK in complex with its methyl-donor cofactor S-adenosyl-L-methionine (SAM). In this model, validated by methyltransferase activity assays on BsTrmK mutants, both domains of BsTrmK participate in tRNA binding. BsTrmK recognises tRNA with very few structural changes in both partner, the non-Watson-Crick R13-A22 base-pair positioning the A22 N1-atom close to the SAM methyl group. Structural characterization of B. subtilis m1A22 tRNA methyltransferase TrmK: insights into tRNA recognition.,Degut C, Roovers M, Barraud P, Brachet F, Feller A, Larue V, Al Refaii A, Caillet J, Droogmans L, Tisne C Nucleic Acids Res. 2019 Apr 1. pii: 5424071. doi: 10.1093/nar/gkz230. PMID:30931478 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also TRNA methyltransferase 3D structures

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