View source for 4iwn


==Crystal structure of a putative methyltransferase CmoA in complex with a novel SAM derivative==
<StructureSection load='4iwn' size='340' side='right'caption='[[4iwn]], [[Resolution|resolution]] 1.73&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4iwn]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4IWN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4IWN 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]] 1.73&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GEK:(2S)-4-[{[(2S,3S,4R,5R)-5-(6-AMINO-9H-PURIN-9-YL)-3,4-DIHYDROXYTETRAHYDROFURAN-2-YL]METHYL}(CARBOXYLATOMETHYL)SULFONIO]-2-AMMONIOBUTANOATE'>GEK</scene>, <scene name='pdbligand=MPD:(4S)-2-METHYL-2,4-PENTANEDIOL'>MPD</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=4iwn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4iwn OCA], [https://pdbe.org/4iwn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4iwn RCSB], [https://www.ebi.ac.uk/pdbsum/4iwn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4iwn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CMOA_ECOLI CMOA_ECOLI] Catalyzes the conversion of 5-methoxyuridine (mo5U) to uridine-5-oxyacetic acid (cmo5U) at position 34 in tRNA. May also participate in the methylation of uridine-5-oxyacetic acid (cmo5U) to uridine-5-oxyacetic acid methyl ester (mcmo5U) (By similarity).
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Uridine at position 34 of bacterial transfer RNAs is commonly modified to uridine-5-oxyacetic acid (cmo(5)U) to increase the decoding capacity. The protein CmoA is involved in the formation of cmo(5)U and was annotated as an S-adenosyl-L-methionine-dependent (SAM-dependent) methyltransferase on the basis of its sequence homology to other SAM-containing enzymes. However, both the crystal structure of Escherichia coli CmoA at 1.73 A resolution and mass spectrometry demonstrate that it contains a novel cofactor, S-adenosyl-S-carboxymethyl-L-homocysteine (SCM-SAH), in which the donor methyl group is substituted by a carboxymethyl group. The carboxyl moiety forms a salt-bridge interaction with Arg199 that is conserved in a large group of CmoA-related proteins but is not conserved in other SAM-containing enzymes. This raises the possibility that a number of enzymes that have previously been annotated as SAM-dependent are in fact SCM-SAH-dependent. Indeed, inspection of electron density for one such enzyme with known X-ray structure, PDB entry 1im8, suggests that the active site contains SCM-SAH and not SAM.

S-Adenosyl-S-carboxymethyl-L-homocysteine: a novel cofactor found in the putative tRNA-modifying enzyme CmoA.,Byrne RT, Whelan F, Aller P, Bird LE, Dowle A, Lobley CM, Reddivari Y, Nettleship JE, Owens RJ, Antson AA, Waterman DG Acta Crystallogr D Biol Crystallogr. 2013 Jun;69(Pt 6):1090-8. doi:, 10.1107/S0907444913004939. Epub 2013 May 15. PMID:23695253<ref>PMID:23695253</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4iwn" style="background-color:#fffaf0;"></div>

==See Also==
*[[TRNA methyltransferase 3D structures|TRNA methyltransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Aller P]]
[[Category: Antson AA]]
[[Category: Byrne RT]]
[[Category: Lobley CM]]
[[Category: Waterman DG]]