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==TrmB complex with SAM==
<StructureSection load='7nyb' size='340' side='right'caption='[[7nyb]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7nyb]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_subtilis_subsp._subtilis_str._168 Bacillus subtilis subsp. subtilis str. 168]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7NYB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7NYB FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SAM:S-ADENOSYLMETHIONINE'>SAM</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7nyb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7nyb OCA], [https://pdbe.org/7nyb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7nyb RCSB], [https://www.ebi.ac.uk/pdbsum/7nyb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7nyb ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TRMB_BACSU TRMB_BACSU] Catalyzes the formation of N(7)-methylguanine at position 46 (m7G46) in tRNA.[HAMAP-Rule:MF_01057]
<div style="background-color:#fffaf0;">
== 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<ref>PMID:34006170</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7nyb" style="background-color:#fffaf0;"></div>

==See Also==
*[[TRNA methyltransferase 3D structures|TRNA methyltransferase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Bacillus subtilis subsp. subtilis str. 168]]
[[Category: Large Structures]]
[[Category: Blersch KF]]
[[Category: Ficner R]]
[[Category: Neumann P]]