1ni6
From Proteopedia
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'''Comparisions of the Heme-Free and-Bound Crystal Structures of Human Heme Oxygenase-1''' | '''Comparisions of the Heme-Free and-Bound Crystal Structures of Human Heme Oxygenase-1''' | ||
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[[Category: Schuller, D J.]] | [[Category: Schuller, D J.]] | ||
[[Category: Shimizu, H.]] | [[Category: Shimizu, H.]] | ||
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| - | [[Category: | + | [[Category: Heme oxygenase-1]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 02:33:49 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 23:33, 2 May 2008
Comparisions of the Heme-Free and-Bound Crystal Structures of Human Heme Oxygenase-1
Contents |
Overview
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.
Disease
Known disease associated with this structure: Heme oxygenase-1 deficiency OMIM:[141250]
About this Structure
1NI6 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
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 Page seeded by OCA on Sat May 3 02:33:49 2008
