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| | <StructureSection load='5kva' size='340' side='right'caption='[[5kva]], [[Resolution|resolution]] 1.83Å' scene=''> | | <StructureSection load='5kva' size='340' side='right'caption='[[5kva]], [[Resolution|resolution]] 1.83Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[5kva]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Andropogon_sorghum Andropogon sorghum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5KVA OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=5KVA FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[5kva]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Sorghum_bicolor Sorghum bicolor]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5KVA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5KVA FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=SAM:S-ADENOSYLMETHIONINE'>SAM</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.827Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">Sb10g004540, SORBIDRAFT_10g004540 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=4558 Andropogon sorghum])</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=SAM:S-ADENOSYLMETHIONINE'>SAM</scene></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=5kva FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5kva OCA], [http://pdbe.org/5kva PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5kva RCSB], [http://www.ebi.ac.uk/pdbsum/5kva PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5kva ProSAT]</span></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=5kva FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5kva OCA], [https://pdbe.org/5kva PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5kva RCSB], [https://www.ebi.ac.uk/pdbsum/5kva PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5kva ProSAT]</span></td></tr> |
| | </table> | | </table> |
| - | <div style="background-color:#fffaf0;">
| + | == Function == |
| - | == Publication Abstract from PubMed == | + | [https://www.uniprot.org/uniprot/C5Z4W3_SORBI C5Z4W3_SORBI] |
| - | Caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) is an S-adenosyl methionine (SAM)-dependent O-methyltransferase responsible for methylation of the meta-hydroxyl group of caffeoyl-CoA, on the pathway to monolignols with their ring methoxylation status characteristic of guaiacyl or syringyl units in lignin. In order to better understand the unique class of type-2 O-methyltransferases from monocots, we have characterized CCoAOMT from sorghum (Sorghum bicolor) (SbCCoAOMT), including the SAM binary complex crystal structure, steady state enzyme kinetics, isothermal titration calorimetry (ITC), inductively coupled plasma-optical emission spectroscopy (ICP-OES) and molecular docking. Key amino acid residues were validated with site-directed mutagenesis. ITC data indicated a sequential binding mechanism for SbCCoAOMT, wherein SAM binds prior to caffeoyl-CoA, and the enzyme showed allosteric behavior with respect to it. 5-Hydroxyferuloyl-CoA was not a substrate for SbCCoAOMT. We propose a catalytic mechanism in which Lys180 acts as a catalytic base and deprotonates the reactive hydroxyl group of caffeoyl-CoA. This deprotonation is facilitated by the coordination of the reactive hydroxyl group by Ca2+ in the active site, lowering the pKa of the 3'-OH group. Collectively, these data give a new perspective on the catalytic mechanism of CCoAOMTs and provide a basis for the functional diversity exhibited by type-2 plant OMTs that contain a unique insertion loop (residues 208-231) conferring affinity for phenylpropanoid-CoA thioesters.
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| - | Determination of the structure and catalytic mechanism of Sorghum bicolor caffeoyl-CoA O-methyltransferase.,Walker AM, Sattler SA, Regner MR, Jones JP, Ralph J, Vermerris W, Sattler SE, Kang C Plant Physiol. 2016 Jul 25. pii: pp.00845.2016. PMID:27457122<ref>PMID:27457122</ref>
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| - | | + | |
| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| - | </div>
| + | |
| - | <div class="pdbe-citations 5kva" style="background-color:#fffaf0;"></div>
| + | |
| - | == References ==
| + | |
| - | <references/>
| + | |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Andropogon sorghum]] | |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Jones, J P]] | + | [[Category: Sorghum bicolor]] |
| - | [[Category: Kang, C]] | + | [[Category: Jones JP]] |
| - | [[Category: Ralph, J]] | + | [[Category: Kang C]] |
| - | [[Category: Regner, M]] | + | [[Category: Ralph J]] |
| - | [[Category: Sattler, S A]] | + | [[Category: Regner M]] |
| - | [[Category: Sattler, S E]] | + | [[Category: Sattler SA]] |
| - | [[Category: Vermerris, W]] | + | [[Category: Sattler SE]] |
| - | [[Category: Walker, A M]] | + | [[Category: Vermerris W]] |
| - | [[Category: Caffeoyl-coa o-methyltransferase]]
| + | [[Category: Walker AM]] |
| - | [[Category: Ccoaomt]]
| + | |
| - | [[Category: Ccomt omt]]
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| - | [[Category: Coenzyme some]]
| + | |
| - | [[Category: Methyltransferase]]
| + | |
| - | [[Category: Sam o-methyltransferase]]
| + | |
| - | [[Category: Sbccoaomt]]
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| - | [[Category: Transferase]]
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