View source for 4wd4


==Crystal structure of human HO1 H25R==
<StructureSection load='4wd4' size='340' side='right'caption='[[4wd4]], [[Resolution|resolution]] 2.95&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4wd4]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4WD4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4WD4 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]] 2.95&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE+ETHANESULFONIC+ACID'>EPE</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=4wd4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4wd4 OCA], [https://pdbe.org/4wd4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4wd4 RCSB], [https://www.ebi.ac.uk/pdbsum/4wd4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4wd4 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/HMOX1_HUMAN HMOX1_HUMAN] Defects in HMOX1 are the cause of heme oxygenase 1 deficiency (HMOX1D) [MIM:[https://omim.org/entry/614034 614034]. A disease characterized by impaired stress hematopoiesis, resulting in marked erythrocyte fragmentation and intravascular hemolysis, coagulation abnormalities, endothelial damage, and iron deposition in renal and hepatic tissues. Clinical features include persistent hemolytic anemia, asplenia, nephritis, generalized erythematous rash, growth retardation and hepatomegaly.<ref>PMID:9884342</ref> 
== Function ==
[https://www.uniprot.org/uniprot/HMOX1_HUMAN HMOX1_HUMAN] 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.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Heme oxygenase (HO) is a ubiquitous enzyme with key roles in inflammation, cell signaling, heme disposal, and iron acquisition. HO catalyzes the oxidative conversion of heme to biliverdin (BV) using a conserved histidine to coordinate the iron atom of bound heme. This His-heme interaction has been regarded as being essential for enzyme activity, because His-to-Ala mutants fail to convert heme to biliverdin in vitro. We probed a panel of proximal His mutants of cyanobacterial, human, and plant HO enzymes using a live-cell activity assay based on heterologous co-expression in Escherichia coli of each HO mutant and a fluorescent biliverdin biosensor. In contrast to in vitro studies with purified proteins, we observed that multiple HO mutants retained significant activity within the intracellular environment of bacteria. X-ray crystallographic structures of human HO1 H25R with bound heme and additional functional studies suggest that HO mutant activity inside these cells does not involve heme ligation by a proximal amino acid. Our study reveals unexpected plasticity in the active site binding interactions with heme that can support HO activity within cells, suggests important contributions by the surrounding active site environment to HO catalysis, and can guide efforts to understand the evolution and divergence of HO function.

In-Cell Enzymology To Probe His-Heme Ligation in Heme Oxygenase Catalysis.,Sigala PA, Morante K, Tsumoto K, Caaveiro JM, Goldberg DE Biochemistry. 2016 Aug 30;55(34):4836-49. doi: 10.1021/acs.biochem.6b00562. Epub , 2016 Aug 15. PMID:27490825<ref>PMID:27490825</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4wd4" style="background-color:#fffaf0;"></div>

==See Also==
*[[Heme oxygenase 3D structures|Heme oxygenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Caaveiro JMM]]
[[Category: Morante K]]
[[Category: Sigala P]]
[[Category: Tsumoto K]]