View source for 6bdy


==Crystal Structure of the MetH Reactivation Domain bound to Sinefungin==
<StructureSection load='6bdy' size='340' side='right'caption='[[6bdy]], [[Resolution|resolution]] 1.51&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6bdy]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6BDY OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6BDY 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]] 1.512&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SFG:SINEFUNGIN'>SFG</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=6bdy FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6bdy OCA], [https://pdbe.org/6bdy PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6bdy RCSB], [https://www.ebi.ac.uk/pdbsum/6bdy PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6bdy ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/METH_ECOLI METH_ECOLI] Catalyzes the transfer of a methyl group from methyl-cobalamin to homocysteine, yielding enzyme-bound cob(I)alamin and methionine. Subsequently, remethylates the cofactor using methyltetrahydrofolate.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The C-terminal domain of cobalamin-dependent methionine synthase (MetH) has an essential role in catalyzing the reactivation of the enzyme following the oxidation of its cobalamin cofactor. This reactivation occurs through reductive methylation of the cobalamin using S-adenosylmethionine (AdoMet) as the methyl donor. Herein, we examine the molecular recognition of AdoMet by the MetH reactivation domain utilizing structural, biochemical, and computational approaches. Crystal structures of the Escherichia coli MetH reactivation domain in complex with AdoMet, the methyl transfer product S-adenosylhomocysteine (AdoHcy), and the AdoMet analogue inhibitor sinefungin illustrate that the ligands exhibit an analogous conformation within the solvent-exposed substrate binding cleft of the enzyme. AdoMet binding is stabilized by an intramolecular sulfur-oxygen chalcogen bond between the sulfonium and carboxylate groups of the substrate and by water-mediated carbon-oxygen hydrogen bonding between the sulfonium cation and the side chains of Glu1097 and Glu1128 that bracket the substrate binding cleft. AdoMet and sinefungin exhibited similar binding affinities for the MetH reactivation domain, whereas AdoHcy displayed an affinity for the enzyme that was an order of magnitude lower. Mutations of Glu1097 and Glu1128 diminished the AdoMet/AdoHcy binding selectivity ratio to approximately 2-fold, underscoring the role of these residues in enabling the enzyme to discriminate between the substrate and product. Together, these findings indicate that Glu1097 and Glu1128 in MetH promote high-affinity recognition of AdoMet and that sinefungin and potentially other AdoMet-based methyltransferase inhibitors can abrogate MetH reactivation, which would result in off-target effects associated with alterations in methionine homeostasis and one-carbon metabolism.

Water-Mediated Carbon-Oxygen Hydrogen Bonding Facilitates S-Adenosylmethionine Recognition in the Reactivation Domain of Cobalamin-Dependent Methionine Synthase.,Fick RJ, Clay MC, Vander Lee L, Scheiner S, Al-Hashimi H, Trievel RC Biochemistry. 2018 May 21. doi: 10.1021/acs.biochem.8b00375. PMID:29733595<ref>PMID:29733595</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6bdy" style="background-color:#fffaf0;"></div>

==See Also==
*[[Methionine synthase 3D structures|Methionine synthase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Fick RJ]]
[[Category: Trievel RC]]
[[Category: Vander Lee LP]]