3bq5

<table><tr><td colspan='2'>[[3bq5]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Atcc_43589 Atcc 43589]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BQ5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3BQ5 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=HCS:2-AMINO-4-MERCAPTO-BUTYRIC+ACID'>HCS</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1xdj|1xdj]], [[3bof|3bof]], [[3bol|3bol]], [[3bq6|3bq6]]</div></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">metE ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=2336 ATCC 43589])</td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/5-methyltetrahydropteroyltriglutamate--homocysteine_S-methyltransferase 5-methyltetrahydropteroyltriglutamate--homocysteine S-methyltransferase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.14 2.1.1.14] </span></td></tr>

[[https://www.uniprot.org/uniprot/METE_THEMA METE_THEMA]] Catalyzes the transfer of a methyl group from 5-methyltetrahydrofolate to homocysteine resulting in methionine formation (By similarity).

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== Publication Abstract from PubMed ==

Enzymes possessing catalytic zinc centers perform a variety of fundamental processes in nature, including methyl transfer to thiols. Cobalamin-independent (MetE) and cobalamin-dependent (MetH) methionine synthases are two such enzyme families. Although they perform the same net reaction, transfer of a methyl group from methyltetrahydrofolate to homocysteine (Hcy) to form methionine, they display markedly different catalytic strategies, modular organization, and active site zinc centers. Here we report crystal structures of zinc-replete MetE and MetH, both in the presence and absence of Hcy. Structural investigation of the catalytic zinc sites of these two methyltransferases reveals an unexpected inversion of zinc geometry upon binding of Hcy and displacement of an endogenous ligand in both enzymes. In both cases a significant movement of the zinc relative to the protein scaffold accompanies inversion. These structures provide new information on the activation of thiols by zinc-containing enzymes and have led us to propose a paradigm for the mechanism of action of the catalytic zinc sites in these and related methyltransferases. Specifically, zinc is mobile in the active sites of MetE and MetH, and its dynamic nature helps facilitate the active site conformational changes necessary for thiol activation and methyl transfer.

 

== References ==

[[Category: 5-methyltetrahydropteroyltriglutamate--homocysteine S-methyltransferase]]

[[Category: Atcc 43589]]

[[Category: Ludwig, M L]]

[[Category: Pejchal, R]]

[[Category: Smith, J L]]

[[Category: Amino-acid biosynthesis]]

[[Category: Zinc inversion]]