View source for 6emt


==Crystal Structure of dual specific Trm10 construct from Thermococcus kodakaraensis.==
<StructureSection load='6emt' size='340' side='right' caption='[[6emt]], [[Resolution|resolution]] 1.79&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6emt]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"thermococcus_kodakaraensis"_atomi_et_al._2004 "thermococcus kodakaraensis" atomi et al. 2004]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6EMT OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6EMT FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=TRS:2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL'>TRS</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">TK0422 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=311400 "Thermococcus kodakaraensis" Atomi et al. 2004])</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6emt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6emt OCA], [http://pdbe.org/6emt PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6emt RCSB], [http://www.ebi.ac.uk/pdbsum/6emt PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6emt ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/TRM10_THEKO TRM10_THEKO]] Catalyzes the S-adenosyl-L-methionine-dependent formation of either N(1)-methyladenine or N(1)-methylguanine at position 9 (m1A9 or m1G9) in tRNA.<ref>PMID:20525789</ref>  
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
tRNA molecules get heavily modified posttranscriptionally. The N-1 methylation of purines at position 9 of eukaryal and archaeal tRNA is catalyzed by the SPOUT methyltranferase Trm10. Remarkably, while certain Trm10 orthologues are specific for either guanosine or adenosine, others show a dual specificity. Structural and functional studies have been performed on guanosine- and adenosine-specific enzymes. Here we report the structure and biochemical analysis of the dual specificity enzyme from Thermococcus kodakaraensis (TkTrm10). We report the first crystal structure of a construct of this enzyme, consisting of the N-terminal domain and the catalytic SPOUT domain. Moreover, crystal structures of the SPOUT domain, either in the apo form or bound to S-adenosyl-L-methionine or S-adenosyl-L-homocysteine reveal conformational plasticity of two active site loops upon substrate binding. Kinetic analysis shows that TkTrm10 has a high affinity for its tRNA substrates, while the enzyme on its own has a very low methyltransferase activity. Mutation of either of two active site aspartate residues (Asp206 and Asp245) to Asn or Ala results in only modest effects on the N-1 methylation reaction, with a small shift toward a preference for m(1)G formation over m(1)A formation. Only a double D206A/D245A mutation severely impairs activity. These results are in line with the recent finding that the single active-site aspartate was dispensable for activity in the guanosine-specific Trm10 from yeast, and suggest that also dual specificity Trm10 orthologues use a non-canonical tRNA methyltransferase mechanism without residues acting as general base catalysts.

Structural and biochemical analysis of the dual-specificity Trm10 enzyme from Thermococcus kodakaraensis prompts reconsideration of its catalytic mechanism.,Singh RK, Feller A, Roovers M, Van Elder D, Wauters L, Droogmans L, Versees W RNA. 2018 May 30. pii: rna.064345.117. doi: 10.1261/rna.064345.117. PMID:29848639<ref>PMID:29848639</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6emt" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Thermococcus kodakaraensis atomi et al. 2004]]
[[Category: Singh, R K]]
[[Category: Versees, W]]
[[Category: Dual specificity enzyme]]
[[Category: Mtase]]
[[Category: Rna binding protein]]
[[Category: Spout]]
[[Category: Trm10]]