View source for 1ix4


==Crystal Structure of Rat Heme Oxygenase-1 in complex with Heme bound to Carbon Monoxide==
<StructureSection load='1ix4' size='340' side='right'caption='[[1ix4]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ix4]] 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=1IX4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1IX4 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CMO:CARBON+MONOXIDE'>CMO</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</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=1ix4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ix4 OCA], [https://pdbe.org/1ix4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ix4 RCSB], [https://www.ebi.ac.uk/pdbsum/1ix4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ix4 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/HMOX1_RAT HMOX1_RAT] Heme oxygenase cleaves the heme ring at the alpha methene bridge to form biliverdin. Biliverdin is subsequently converted to bilirubin by biliverdin reductase. Under physiological conditions, the activity of heme oxygenase is highest in the spleen, where senescent erythrocytes are sequestrated and destroyed.
== 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/ix/1ix4_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=1ix4 ConSurf].
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== Publication Abstract from PubMed ==
Heme oxygenase (HO) catalyzes heme degradation by utilizing O(2) and reducing equivalents to produce biliverdin IX alpha, iron, and CO. To avoid product inhibition, the heme[bond]HO complex (heme[bond]HO) is structured to markedly increase its affinity for O(2) while suppressing its affinity for CO. We determined the crystal structures of rat ferrous heme[bond]HO and heme[bond]HO bound to CO, CN(-), and NO at 2.3, 1.8, 2.0, and 1.7 A resolution, respectively. The heme pocket of ferrous heme-HO has the same conformation as that of the previously determined ferric form, but no ligand is visible on the distal side of the ferrous heme. Fe[bond]CO and Fe[bond]CN(-) are tilted, whereas the Fe[bond]NO is bent. The structure of heme[bond]HO bound to NO is identical to that bound to N(3)(-), which is also bent as in the case of O(2). Notably, in the CO- and CN(-)-bound forms, the heme and its ligands shift toward the alpha-meso carbon, and the distal F-helix shifts in the opposite direction. These shifts allow CO or CN(-) to bind in a tilted fashion without a collision between the distal ligand and Gly139 O and cause disruption of one salt bridge between the heme and basic residue. The structural identity of the ferrous and ferric states of heme[bond]HO indicates that these shifts are not produced on reduction of heme iron. Neither such conformational changes nor a heme shift occurs on NO or N(3)(-) binding. Heme[bond]HO therefore recognizes CO and O(2) by their binding geometries. The marked reduction in the ratio of affinities of CO to O(2) for heme[bond]HO achieved by an increase in O(2) affinity [Migita, C. T., Matera, K. M., Ikeda-Saito, M., Olson, J. S., Fujii, H., Yoshimura, T., Zhou, H., and Yoshida, T. (1998) J. Biol. Chem. 273, 945-949] is explained by hydrogen bonding and polar interactions that are favorable for O(2) binding, as well as by characteristic structural changes in the CO-bound form.

Crystal structures of ferrous and CO-, CN(-)-, and NO-bound forms of rat heme oxygenase-1 (HO-1) in complex with heme: structural implications for discrimination between CO and O2 in HO-1.,Sugishima M, Sakamoto H, Noguchi M, Fukuyama K Biochemistry. 2003 Aug 26;42(33):9898-905. PMID:12924938<ref>PMID:12924938</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 1ix4" style="background-color:#fffaf0;"></div>

==See Also==
*[[Heme oxygenase 3D structures|Heme oxygenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Rattus norvegicus]]
[[Category: Fukuyama K]]
[[Category: Hayashi S]]
[[Category: Noguchi M]]
[[Category: Omata Y]]
[[Category: Sakamoto H]]
[[Category: Sugishima M]]