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== | ==Comparisions of the Heme-Free and-Bound Crystal Structures of Human Heme Oxygenase-1== | ||
<StructureSection load='1ni6' size='340' side='right'caption='[[1ni6]], [[Resolution|resolution]] 2.10Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1ni6]] 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=1NI6 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NI6 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]] 2.1Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=PRD_900006:trehalose'>PRD_900006</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=1ni6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ni6 OCA], [https://pdbe.org/1ni6 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ni6 RCSB], [https://www.ebi.ac.uk/pdbsum/1ni6 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ni6 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. | |||
== 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/ni/1ni6_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=1ni6 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Heme oxygenase (HO) catalyzes the degradation of heme to biliverdin. The crystal structure of human HO-1 in complex with heme reveals a novel helical structure with conserved glycines in the distal helix, providing flexibility to accommodate substrate binding and product release (Schuller, D. J., Wilks, A., Ortiz de Montellano, P. R., and Poulos, T. L. (1999) Nat. Struct. Biol. 6, 860-867). To structurally understand the HO catalytic pathway in more detail, we have determined the crystal structure of human apo-HO-1 at 2.1 A and a higher resolution structure of human HO-1 in complex with heme at 1.5 A. Although the 1.5-A heme.HO-1 model confirms our initial analysis based on the 2.08-A model, the higher resolution structure has revealed important new details such as a solvent H-bonded network in the active site that may be important for catalysis. Because of the absence of the heme, the distal and proximal helices that bracket the heme plane in the holo structure move farther apart in the apo structure, thus increasing the size of the active-site pocket. Nevertheless, the relative positioning and conformation of critical catalytic residues remain unchanged in the apo structure compared with the holo structure, but an important solvent H-bonded network is missing in the apoenzyme. It thus appears that the binding of heme and a tightening of the structure around the heme stabilize the solvent H-bonded network required for proper catalysis. | Heme oxygenase (HO) catalyzes the degradation of heme to biliverdin. The crystal structure of human HO-1 in complex with heme reveals a novel helical structure with conserved glycines in the distal helix, providing flexibility to accommodate substrate binding and product release (Schuller, D. J., Wilks, A., Ortiz de Montellano, P. R., and Poulos, T. L. (1999) Nat. Struct. Biol. 6, 860-867). To structurally understand the HO catalytic pathway in more detail, we have determined the crystal structure of human apo-HO-1 at 2.1 A and a higher resolution structure of human HO-1 in complex with heme at 1.5 A. Although the 1.5-A heme.HO-1 model confirms our initial analysis based on the 2.08-A model, the higher resolution structure has revealed important new details such as a solvent H-bonded network in the active site that may be important for catalysis. Because of the absence of the heme, the distal and proximal helices that bracket the heme plane in the holo structure move farther apart in the apo structure, thus increasing the size of the active-site pocket. Nevertheless, the relative positioning and conformation of critical catalytic residues remain unchanged in the apo structure compared with the holo structure, but an important solvent H-bonded network is missing in the apoenzyme. It thus appears that the binding of heme and a tightening of the structure around the heme stabilize the solvent H-bonded network required for proper catalysis. | ||
Comparison of the heme-free and -bound crystal structures of human heme oxygenase-1.,Lad L, Schuller DJ, Shimizu H, Friedman J, Li H, Ortiz de Montellano PR, Poulos TL J Biol Chem. 2003 Mar 7;278(10):7834-43. Epub 2002 Dec 24. PMID:12500973<ref>PMID:12500973</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1ni6" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Heme oxygenase 3D structures|Heme oxygenase 3D structures]] | |||
[ | == References == | ||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Friedman | [[Category: Friedman J]] | ||
[[Category: Lad | [[Category: Lad L]] | ||
[[Category: Li | [[Category: Li H]] | ||
[[Category: | [[Category: Ortiz de Montellano PR]] | ||
[[Category: Poulos | [[Category: Poulos TL]] | ||
[[Category: Schuller | [[Category: Schuller DJ]] | ||
[[Category: Shimizu | [[Category: Shimizu H]] | ||