View source for 3ssn

==MycE Methyltransferase from the Mycinamycin Biosynthetic Pathway in Complex with Mg, SAH, and Mycinamycin VI==
<StructureSection load='3ssn' size='340' side='right' caption='[[3ssn]], [[Resolution|resolution]] 2.39&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3ssn]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Micromonospora_griseorubida Micromonospora griseorubida]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3SSN OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3SSN FirstGlance]. <br>
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=DMS:DIMETHYL+SULFOXIDE'>DMS</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=MVI:MYCINAMICIN+VI'>MVI</scene>, <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene><br>
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3ssm|3ssm]], [[3sso|3sso]]</td></tr>
<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">mycE ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=28040 Micromonospora griseorubida])</td></tr>
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3ssn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ssn OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3ssn RCSB], [http://www.ebi.ac.uk/pdbsum/3ssn PDBsum]</span></td></tr>
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== Publication Abstract from PubMed ==
O-linked methylation of sugar substituents is a common modification in the biosynthesis of many natural products and is catalyzed by multiple families of S-adenosyl-L-methionine (SAM or AdoMet)-dependent methyltransferases (MTs). Mycinamicins, potent antibiotics from Micromonospora griseorubida, can be methylated at two positions on a 6-deoxyallose substituent. The first methylation is catalyzed by MycE, a SAM- and metal-dependent MT. Crystal structures were determined for MycE bound to the product S-adenosyl-L-homocysteine (AdoHcy) and magnesium, both with and without the natural substrate mycinamicin VI. This represents the first structure of a natural product sugar MT in complex with its natural substrate. MycE is a tetramer of a two-domain polypeptide, comprising a C-terminal catalytic MT domain and an N-terminal auxiliary domain, which is important for quaternary assembly and for substrate binding. The symmetric MycE tetramer has a novel MT organization in which each of the four active sites is formed at the junction of three monomers within the tetramer. The active-site structure supports a mechanism in which a conserved histidine acts as a general base, and the metal ion helps to position the methyl acceptor and to stabilize a hydroxylate intermediate. A conserved tyrosine is suggested to support activity through interactions with the transferred methyl group from the SAM methyl donor. The structure of the free enzyme reveals a dramatic order-disorder transition in the active site relative to the S-adenosyl-L-homocysteine complexes, suggesting a mechanism for product/substrate exchange through concerted movement of five loops and the polypeptide C-terminus.

A new structural form in the SAM/metal-dependent omethyltransferase family: MycE from the mycinamicin biosynthetic pathway.,Akey DL, Li S, Konwerski JR, Confer LA, Bernard SM, Anzai Y, Kato F, Sherman DH, Smith JL J Mol Biol. 2011 Oct 21;413(2):438-50. Epub 2011 Aug 23. PMID:21884704<ref>PMID:21884704</ref>

From MEDLINEÂ®/PubMedÂ®, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Micromonospora griseorubida]]
[[Category: Akey, D L.]]
[[Category: Smith, J L.]]
[[Category: Macrolide]]
[[Category: Methyltransferase]]
[[Category: Natural product]]
[[Category: Rossmann fold]]
[[Category: Transferase-antibiotic complex]]