View source for 4ilz


==Structural and kinetic study of an internal substrate binding site of dehaloperoxidase-hemoglobin A from Amphitrite ornata==
<StructureSection load='4ilz' size='340' side='right'caption='[[4ilz]], [[Resolution|resolution]] 1.91&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4ilz]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Amphitrite_ornata Amphitrite ornata]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4ILZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4ILZ 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]] 1.91&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=IPA:ISOPROPYL+ALCOHOL'>IPA</scene>, <scene name='pdbligand=OXY:OXYGEN+MOLECULE'>OXY</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=TBP:2,4,6-TRIBROMOPHENOL'>TBP</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=4ilz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ilz OCA], [https://pdbe.org/4ilz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ilz RCSB], [https://www.ebi.ac.uk/pdbsum/4ilz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ilz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q9NAV8_9ANNE Q9NAV8_9ANNE] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
X-ray crystal structures of dehaloperoxidase-hemoglobin A (DHP A) from Amphitrite ornata soaked with substrate, 2,4,6-tribromophenol (2,4,6-TBP), in buffer solvent with added methanol (MeOH), 2-propanol (2-PrOH) and dimethylsulfoxide (DMSO) reveal an internal substrate binding site deep in the distal pocket above the -edge of the heme that is distinct from the previously determined internal inhibitor binding site. The peroxidase function of DHP A has most often been studied using 2,4,6-trichlorophenol (2,4,6-TCP) as a substrate analog because of the low solubility of 2,4,6-TBP in aqueous buffer solution. Previous studies at low substrate concentration pointed towards the binding of substrate 2,4,6-TCP at an external site near the exterior heme - or -edge as observed in the class of heme peroxidases. Here we report that the turnover frequencies of both substrates 2,4,6-TCP and 2,4,6-TBP deviate from Michaelis-Menten kinetics at high concentration. The turnover frequency reaches a maximum in the range 1400-1700 M with a decrease in rate at higher concentrations that is both substrate and solvent dependent. The X-ray crystal structure is consistent the presence of an internal active site above the heme -edge, in which the substrate would be oxidized in two consecutive steps inside the enzyme, followed by attack by H2O via a water channel in the protein. The physiological role of the internal site may involve interactions with any of a number of aromatic toxins found in benthic ecosystems where A. ornata resides.

Structural and kinetic study of an internal substrate binding site of dehaloperoxidase-hemoglobin A from Amphitrite ornata.,Zhao J, de Serrano VS, Zhao J, Le PD, Franzen S Biochemistry. 2013 Mar 12. PMID:23480178<ref>PMID:23480178</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4ilz" style="background-color:#fffaf0;"></div>

==See Also==
*[[Dehaloperoxidase 3D structures|Dehaloperoxidase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Amphitrite ornata]]
[[Category: Large Structures]]
[[Category: Franzen S]]
[[Category: Zhao J]]
[[Category: De Serrano VS]]