View source for 3lga


==Crystal structure of P. abyssi tRNA m1A58 methyltransferase in complex with S-adenosyl-L-homocysteine==
<StructureSection load='3lga' size='340' side='right'caption='[[3lga]], [[Resolution|resolution]] 2.05&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3lga]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Pyrococcus_abyssi_GE5 Pyrococcus abyssi GE5]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3LGA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3LGA 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]] 2.05&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=3lga FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3lga OCA], [https://pdbe.org/3lga PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3lga RCSB], [https://www.ebi.ac.uk/pdbsum/3lga PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3lga ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TRMI_PYRAB TRMI_PYRAB] Catalyzes the S-adenosyl-L-methionine-dependent formation of N(1)-methyladenosine at position(s) 57 (m1A57) and 58 (m1A58) in the T-loop of some tRNAs. Methylates the first adenine of an AA sequence.<ref>PMID:14739239</ref> <ref>PMID:20483913</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/lg/3lga_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=3lga ConSurf].
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== Publication Abstract from PubMed ==
The S-adenosyl-l-methionine dependent methylation of adenine 58 in the T-loop of tRNAs is essential for cell growth in yeast or for adaptation to high temperatures in thermophilic organisms. In contrast to bacterial and eukaryotic tRNA m(1)A58 methyltransferases that are site-specific, the homologous archaeal enzyme from Pyrococcus abyssi catalyzes the formation of m(1)A also at the adjacent position 57, m(1)A57 being a precursor of 1-methylinosine. We report here the crystal structure of P. abyssi tRNA m(1)A57/58 methyltransferase ((Pab)TrmI), in complex with S-adenosyl-l-methionine or S-adenosyl-l-homocysteine in three different space groups. The fold of the monomer and the tetrameric architecture are similar to those of the bacterial enzymes. However, the inter-monomer contacts exhibit unique features. In particular, four disulfide bonds contribute to the hyperthermostability of the archaeal enzyme since their mutation lowers the melting temperature by 16.5 degrees C. His78 in conserved motif X, which is present only in TrmIs from the Thermococcocales order, lies near the active site and displays two alternative conformations. Mutagenesis indicates His78 is important for catalytic efficiency of (Pab)TrmI. When A59 is absent in tRNA(Asp), only A57 is modified. Identification of the methylated positions in tRNAAsp by mass spectrometry confirms that (Pab)TrmI methylates the first adenine of an AA sequence.

Insights into the hyperthermostability and unusual region-specificity of archaeal Pyrococcus abyssi tRNA m1A57/58 methyltransferase.,Guelorget A, Roovers M, Guerineau V, Barbey C, Li X, Golinelli-Pimpaneau B Nucleic Acids Res. 2010 May 18. PMID:20483913<ref>PMID:20483913</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[SAM-dependent methyltrasferase 3D structures|SAM-dependent methyltrasferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Pyrococcus abyssi GE5]]
[[Category: Golinelli-Pimpaneau B]]
[[Category: Guelorget A]]