View source for 4iex


==unliganded room-temp Cysteine Dioxygenase at pH 6.2==
<StructureSection load='4iex' size='340' side='right'caption='[[4iex]], [[Resolution|resolution]] 2.15&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4iex]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4IEX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4IEX 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]] 2.15&#8491;</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='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4iex FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4iex OCA], [https://pdbe.org/4iex PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4iex RCSB], [https://www.ebi.ac.uk/pdbsum/4iex PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4iex ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CDO1_RAT CDO1_RAT] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Mammalian cysteine dioxygenase (CDO) is a mononuclear non-heme iron protein that catalyzes the conversion of cysteine (Cys) to cysteine sulfinic acid by an unclarified mechanism. One structural study revealed that a Cys-persulfenate (or Cys-persulfenic acid) formed in the active site, but quantum mechanical calculations have been used to support arguments that it is not an energetically feasible reaction intermediate. Here, we report a series of high-resolution structures of CDO soaked with Cys at pH values from 4 to 9. Cys binding is minimal at pH&lt;/=5 and persulfenate formation is consistently seen at pH values between 5.5 and 7. Also, a structure determined using laboratory-based X-ray diffraction shows that the persulfenate, with an apparent average O-O separation distance of ~1.8A, is not an artifact of synchrotron radiation. At pH&gt;/=8, the active-site iron shifts from 4- to 5-coordinate, and Cys soaks reveal a complex with Cys, but no dioxygen, bound. This 'Cys-only' complex differs in detail from a previously published 'Cys-only' complex, which we reevaluate and conclude is not reliable. The high-resolution structures presented here do not resolve the CDO mechanism but do imply that an iron-bound persulfenate (or persulfenic acid) is energetically accessible in the CDO active site, and that CDO active-site chemistry in the crystals is influenced by protonation/deprotonation events with effective pKa values near ~5.5 and ~7.5 that influence Cys binding and oxygen binding/reactivity, respectively. Furthermore, this work provides reliable ligand-bound models for guiding future mechanistic considerations.

Cysteine Dioxygenase Structures from pH4 to 9: Consistent Cys-Persulfenate Formation at Intermediate pH and a Cys-Bound Enzyme at Higher pH.,Driggers CM, Cooley RB, Sankaran B, Hirschberger LL, Stipanuk MH, Karplus PA J Mol Biol. 2013 Jun 7. pii: S0022-2836(13)00358-6. doi:, 10.1016/j.jmb.2013.05.028. PMID:23747973<ref>PMID:23747973</ref>

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

==See Also==
*[[Dioxygenase 3D structures|Dioxygenase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Rattus norvegicus]]
[[Category: Cooley RB]]
[[Category: Driggers CM]]
[[Category: Karplus PA]]