View source for 8iaa


==SpnK Methyltransferase from the Spinosyn Biosynthetic Pathway in Complex with SAH==
<StructureSection load='8iaa' size='340' side='right'caption='[[8iaa]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8iaa]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharopolyspora_spinosa Saccharopolyspora spinosa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8IAA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8IAA 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]] 2.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=8iaa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8iaa OCA], [https://pdbe.org/8iaa PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8iaa RCSB], [https://www.ebi.ac.uk/pdbsum/8iaa PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8iaa ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q9ALN2_SACSN Q9ALN2_SACSN] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Rhamnose methylation of spinosyn critical for insecticidal activity is orchestrated by substrate specificity of three S-adenosyl-L-methionine (SAM) dependent methyltransferases (MTs). Previous in vitro enzymatic assays indicate that 3'-O-MT SpnK accepts the rhamnosylated aglycone (RAGL) and 2'-O-methylated RAGL as substrates, but does not tolerate the presence of a methoxy moiety at the O-4' position of the rhamnose unit. Here we solved the crystal structures of apo and ligand-bound SpnK, and used molecular dynamic (MD) simulations to decipher the molecular basis of substrate specificity. SpnK assembles into a tetramer, with each set of three monomers forming an integrated substrate binding pocket. The MD simulations of SpnK complexed with RAGL or 2'-O-methylated RAGL revealed that the 4'-hydroxyl of the rhamnose unit formed a hydrogen bond with a conserved Asp299 of the catalytic center, which is disrupted in structures of SpnK complexed with 4'-O-methylated RAGL or 2',4'-di-O-methylated RAGL. Comparison with SpnI methylating the C2'-hydroxyl of RAGL reveals a correlation between a DLQT/DLWT motif and the selectivity of rhamnose O-MTs. Together, our structural and computational results revealed the structural basis of substrate specificity of rhamnose O-MTs and would potentially help the engineering of spinosyn derivatives.

Structural and computational insights into the regioselectivity of SpnK involved in rhamnose methylation of spinosyn.,Huang S, Ji H, Zheng J Int J Biol Macromol. 2023 Sep 11;253(Pt 3):126763. doi: , 10.1016/j.ijbiomac.2023.126763. PMID:37703985<ref>PMID:37703985</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8iaa" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharopolyspora spinosa]]
[[Category: Huang S]]
[[Category: Zheng J]]