1oqb

<table><tr><td colspan='2'>[[1oqb]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Castor_bean Castor bean]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OQB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1OQB FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE2:FE+(II)+ION'>FE2</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1afr|1afr]], [[1oq4|1oq4]], [[1oq7|1oq7]], [[1oq9|1oq9]]</div></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Acyl-[acyl-carrier-protein]_desaturase Acyl-[acyl-carrier-protein] desaturase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.19.2 1.14.19.2] </span></td></tr>

[[https://www.uniprot.org/uniprot/STAD_RICCO STAD_RICCO]] Converts stearoyl-ACP to oleoyl-ACP by introduction of a cis double bond between carbons Delta(9) and Delta(10) of the acyl chain.

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== Publication Abstract from PubMed ==

Delta9 stearoyl-acyl carrier protein (ACP) desaturase is a mu-oxo-bridged di-iron enzyme, which belongs to the structural class I of large helix bundle proteins and that catalyzes the NADPH and O2-dependent formation of a cis-double bond in stearoyl-ACP. The crystal structures of complexes with azide and acetate, respectively, as well as the apoand single-iron forms of Delta9 stearoyl-ACP desaturase from Ricinus communis have been determined. In the azide complex, the ligand forms a mu-1,3-bridge between the two iron ions in the active site, replacing a loosely bound water molecule. The structure of the acetate complex is similar, with acetate bridging the di-iron center in the same orientation with respect to the di-iron center. However, in this complex, the iron ligand Glu196 has changed its coordination mode from bidentate to monodentate, the first crystallographic observation of a carboxylate shift in Delta9 stearoyl-ACP desaturase. The two complexes are proposed to mimic a mu-1,2 peroxo intermediate present during catalytic turnover. There are striking structural similarities between the di-iron center in the Delta9 stearoyl-ACP desaturase-azide complex and in the reduced rubrerythrin-azide complex. This suggests that Delta9 stearoyl-ACP desaturase might catalyze the formation of water from exogenous hydrogen peroxide at a low rate. From the similarity in iron center structure, we propose that the mu-oxo-bridge in oxidized desaturase is bound to the di-iron center as in rubrerythrin and not as reported for the R2 subunit of ribonucleotide reductase and the hydroxylase subunit of methane monooxygenase. The crystal structure of the one-iron depleted desaturase species demonstrates that the affinities for the two iron ions comprising the di-iron center are not equivalent, Fe1 being the higher affinity site and Fe2 being the lower affinity site.

Azide and acetate complexes plus two iron-depleted crystal structures of the di-iron enzyme delta9 stearoyl-acyl carrier protein desaturase. Implications for oxygen activation and catalytic intermediates.,Moche M, Shanklin J, Ghoshal A, Lindqvist Y J Biol Chem. 2003 Jul 4;278(27):25072-80. Epub 2003 Apr 18. PMID:12704186<ref>PMID:12704186</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Castor bean]]

[[Category: Ghoshal, A K]]

[[Category: Lindqvist, Y]]

[[Category: Moche, M]]

[[Category: Shanklin, J]]

[[Category: Oxidoreductase]]