7nyb

TrmB complex with SAM

spinqualitylabelsall models 7nyb, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7nyb is a 2 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 2.5Å Ligands: SAM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TRMB_BACSU Catalyzes the formation of N(7)-methylguanine at position 46 (m7G46) in tRNA.[HAMAP-Rule:MF_01057] Publication Abstract from PubMed TrmB belongs to the class I S-adenosylmethionine (SAM)-dependent methyltransferases (MTases) and introduces a methyl group to guanine at position 7 (m(7)G) in tRNA. In tRNAs m(7)G is most frequently found at position 46 in the variable loop and forms a tertiary base pair with C13 and U22, introducing a positive charge at G46. The TrmB/Trm8 enzyme family is structurally diverse, as TrmB proteins exist in a monomeric, homodimeric, and heterodimeric form. So far, the exact enzymatic mechanism, as well as the tRNA-TrmB crystal structure is not known. Here we present the first crystal structures of B. subtilis TrmB in complex with SAM and SAH. The crystal structures of TrmB apo and in complex with SAM and SAH have been determined by X-ray crystallography to 1.9 A (apo), 2.5 A (SAM), and 3.1 A (SAH). The obtained crystal structures revealed Tyr193 to be important during SAM binding and MTase activity. Applying fluorescence polarization, the dissociation constant Kd of TrmB and tRNA(Phe) was determined to be 0.12 microM +/- 0.002 microM. Luminescence-based methyltransferase activity assays revealed cooperative effects during TrmB catalysis with half-of-the-site reactivity at physiological SAM concentrations. Structural data retrieved from small-angle x-ray scattering (SAXS), mass-spectrometry of cross-linked complexes, and molecular docking experiments led to the determination of the TrmB-tRNA(Phe) complex structure. Structural model of the M7G46 Methyltransferase TrmB in complex with tRNA.,Blersch KF, Burchert JP, August SC, Welp L, Neumann P, Koster S, Urlaub H, Ficner R RNA Biol. 2021 May 19:1-14. doi: 10.1080/15476286.2021.1925477. PMID:34006170 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also TRNA methyltransferase 3D structures

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