View source for 2hfj


==Pikromycin thioesterase with covalent pentaketide affinity label==
<StructureSection load='2hfj' size='340' side='right'caption='[[2hfj]], [[Resolution|resolution]] 1.95&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2hfj]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptomyces_venezuelae Streptomyces venezuelae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2HFJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2HFJ 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]] 1.95&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DMS:DIMETHYL+SULFOXIDE'>DMS</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=YML:[(3R,4S,5S,7R)-4,8-DIHYDROXY-3,5,7-TRIMETHYL-2-OXOOCTYL]PHOSPHONIC+ACID'>YML</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=2hfj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2hfj OCA], [https://pdbe.org/2hfj PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2hfj RCSB], [https://www.ebi.ac.uk/pdbsum/2hfj PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2hfj ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PIKA4_STRVZ PIKA4_STRVZ] Involved in the biosynthesis of 12- and 14-membered ring macrolactone antibiotics such as methymycin and neomethymycin, and pikromycin and narbomycin, respectively. Component of the pikromycin PKS which catalyzes the biosynthesis of both precursors 10-deoxymethynolide (12-membered ring macrolactone) and narbonolide (14-membered ring macrolactone). Chain elongation through PikAI, PikAII and PikAIII followed by thioesterase catalyzed termination results in the production of 10-deoxymethynolide, while continued elongation through PikAIV, followed by thioesterase (TE) catalyzed cyclization results in the biosynthesis of the narbonolide. The thioesterase can use a series of diketide-N-acetylcysteamine (SNAC) thioesters, but has a strong preference for the 2-methyl-3-ketopentanoyl-SNAC over the stereoisomers of 2-methyl-3-hydroxyacyl-SNAC (PubMed:12379101, PubMed:12733905).<ref>PMID:10421766</ref> <ref>PMID:10676969</ref> <ref>PMID:12379101</ref> <ref>PMID:12733905</ref> <ref>PMID:16969372</ref> <ref>PMID:17719493</ref> <ref>PMID:19027305</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/hf/2hfj_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2hfj ConSurf].
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== Publication Abstract from PubMed ==
Polyketides are a class of biologically active microbial and plant-derived metabolites that possess a high degree of structural and functional diversity and include many human therapeutics, among them anti-infective and anti-cancer drugs, growth promoters and anti-parasitic agents. The macrolide antibiotics, characterized by a glycoside-linked macrolactone, constitute an important class of polyketides, including erythromycin and the natural ketolide anti-infective agent pikromycin. Here we describe new mechanistic details of macrolactone ring formation catalyzed by the pikromycin polyketide synthase thioesterase domain from Streptomyces venezuelae. A pentaketide phosphonate mimic of the final pikromycin linear chain-elongation intermediate was synthesized and shown to be an active site affinity label. The crystal structures of the affinity-labeled enzyme and of a 12-membered-ring macrolactone product complex suggest a mechanism for cyclization in which a hydrophilic barrier in the enzyme and structural restraints of the substrate induce a curled conformation to direct macrolactone ring formation.

Structural basis for macrolactonization by the pikromycin thioesterase.,Akey DL, Kittendorf JD, Giraldes JW, Fecik RA, Sherman DH, Smith JL Nat Chem Biol. 2006 Oct;2(10):537-42. Epub 2006 Sep 10. PMID:16969372<ref>PMID:16969372</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2hfj" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Streptomyces venezuelae]]
[[Category: Akey DL]]
[[Category: Fecik RA]]
[[Category: Giraldes JW]]
[[Category: Kittendorf JD]]
[[Category: Sherman DH]]
[[Category: Smith JL]]