View source for 4ymh


==Crystal structure of SAH-bound Podospora anserina methyltransferase PaMTH1==
<StructureSection load='4ymh' size='340' side='right'caption='[[4ymh]], [[Resolution|resolution]] 1.88&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4ymh]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Podospora_anserina Podospora anserina]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4YMH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4YMH 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]] 1.876&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene>, <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</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=4ymh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ymh OCA], [https://pdbe.org/4ymh PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ymh RCSB], [https://www.ebi.ac.uk/pdbsum/4ymh PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ymh ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q9HGR1_PODAS Q9HGR1_PODAS] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Low levels of reactive oxygen species (ROS) act as important signaling molecules but in excess they can damage biomolecules. ROS regulation is therefore of key importance. Several polyphenols in general and flavonoids in particular have the potential to generate hydroxyl radicals, the most hazardous among all ROS. However, the generation of a hydroxyl radical and subsequent ROS formation can be prevented by methylation of the hydroxyl group of the flavonoids. Omethylation is performed by Omethyltransferases, members of the Sadenosylmethionine (SAM)-dependent Omethyltransferase superfamily involved in the secondary metabolism of many species across all kingdoms. In the filamentous fungus Podospora anserina, a well-established aging model, the O-methyltransferase (PaMTH1) was reported to accumulate in total and mitochondrial protein extracts during aging. In vitro functional studies revealed flavonoids and in particular myricetin as its potential substrate. The molecular architecture of PaMTH1 and the mechanism of the methyl transfer reaction remains unknown. Here, we report the crystal structures of PaMTH1 apoenzyme, PaMTH1-SAM (co-factor) and PaMTH1-SAH (by-product) co-complexes refined to 2.0, 1.9 and 1.9 A, respectively. PaMTH1 forms a tight dimer through swapping of the Ntermini. Each monomer adopts the Rossmann-fold typical for many SAM-binding methyltransferases. Structural comparisons between different Omethyltransferases reveal a strikingly similar co-factor binding pocket but differences in the substrate binding pocket indicating specific molecular determinants required for substrate selection. Furthermore, using NMR, mass spectrometry and site-directed active-site mutagenesis, we show that PaMTH1 catalyzes the transfer of the methyl group from SAM to one hydroxyl group of the myricetin in a cation-dependent manner.

Structure and Biophysical Characterization of the S-adenosylmethionine Dependent O-methyltransferase PaMTH1, a Putative Enzyme Accumulating during Senescence of Podospora anserina.,Chatterjee D, Kudlinzki D, Linhard V, Saxena K, Schieborr U, Gande SL, Wurm JP, Wohnert J, Abele R, Rogov VV, Dotsch V, Osiewacz HD, Sreeramulu S, Schwalbe H J Biol Chem. 2015 May 15. pii: jbc.M115.660829. PMID:25979334<ref>PMID:25979334</ref>

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

==See Also==
*[[SAM-dependent methyltrasferase 3D structures|SAM-dependent methyltrasferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Podospora anserina]]
[[Category: Chatterjee D]]
[[Category: Kudlinzki D]]
[[Category: Linhard VL]]
[[Category: Saxena K]]
[[Category: Schwalbe H]]
[[Category: Sreeramulu S]]