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==Crystal structure of glycine sarcosine N-methyltransferase from Methanohalophilus portucalensis in complex with S-adenosylhomocysteine and dimethylglycine==
<StructureSection load='5him' size='340' side='right'caption='[[5him]], [[Resolution|resolution]] 2.34&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5him]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Methanohalophilus_portucalensis_dsm_7471 Methanohalophilus portucalensis dsm 7471]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5HIM OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=5HIM FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DMG:N,N-DIMETHYLGLYCINE'>DMG</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[5hii|5hii]], [[5hij|5hij]], [[5hik|5hik]], [[5hil|5hil]], [[5gwx|5gwx]], [[5h02|5h02]]</td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">gsmt ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=523843 Methanohalophilus portucalensis DSM 7471])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Glycine/sarcosine_N-methyltransferase Glycine/sarcosine N-methyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.156 2.1.1.156] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=5him FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5him OCA], [http://pdbe.org/5him PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5him RCSB], [http://www.ebi.ac.uk/pdbsum/5him PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5him ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Methyltransferases play crucial roles in many cellular processes, and various regulatory mechanisms have evolved to control their activities. For methyltransferases involved in biosynthetic pathways, regulation via feedback inhibition is a commonly employed strategy to prevent excessive accumulation of the pathways' end products. To date, no biosynthetic methyltransferases have been characterized by X-ray crystallography in complex with their corresponding end product. Here, we report the crystal structures of the glycine sarcosine N-methyltransferase from the halophilic archaeon Methanohalophilus portucalensis (MpGSMT), which represents the first structural elucidation of the GSMT methyltransferase family. As the first enzyme in the biosynthetic pathway of the osmoprotectant betaine, MpGSMT catalyzes N-methylation of glycine and sarcosine, and its activity is feedback-inhibited by the end product betaine. A structural analysis revealed that, despite the simultaneous presence of both substrate (sarcosine) and cofactor (S-adenosyl-L-homocysteine; SAH), the enzyme was likely crystallized in an inactive conformation, as additional structural changes are required to complete the active site assembly. Consistent with this interpretation, the bound SAH can be replaced by the methyl donor S-adenosyl-L-methionine without triggering the methylation reaction. Furthermore, the observed conformational state was found to harbor a betaine-binding site, suggesting that betaine may inhibit MpGSMT activity by trapping the enzyme in an inactive form. This work implicates a structural basis by which feedback inhibition of biosynthetic methyltransferases may be achieved.

Structural Analysis of Glycine Sarcosine N-methyltransferase from Methanohalophilus portucalensis Reveals Mechanistic Insights into the Regulation of Methyltransferase Activity.,Lee YR, Lin TS, Lai SJ, Liu MS, Lai MC, Chan NL Sci Rep. 2016 Dec 9;6:38071. doi: 10.1038/srep38071. PMID:27934872<ref>PMID:27934872</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5him" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Glycine/sarcosine N-methyltransferase]]
[[Category: Large Structures]]
[[Category: Methanohalophilus portucalensis dsm 7471]]
[[Category: Chan, N L]]
[[Category: Lai, M C]]
[[Category: Lai, S J]]
[[Category: Lee, Y R]]
[[Category: Lin, T S]]
[[Category: Liu, M S]]
[[Category: Betaine-mediated feedback inhibition]]
[[Category: Class i]]
[[Category: Monomethylation of glycine and sarcosine]]
[[Category: Rate-limiting enzyme in betaine biosynthesis]]
[[Category: Transferase]]