1ivj
From Proteopedia
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'''Crystal Structure of Rat Hemeoxygenase-1 in Complex with Heme and Azide.''' | '''Crystal Structure of Rat Hemeoxygenase-1 in Complex with Heme and Azide.''' | ||
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[[Category: Sakamoto, H.]] | [[Category: Sakamoto, H.]] | ||
[[Category: Sugishima, M.]] | [[Category: Sugishima, M.]] | ||
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| - | [[Category: | + | [[Category: Di-oxygen analog complex]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 20:28:18 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 17:28, 2 May 2008
Crystal Structure of Rat Hemeoxygenase-1 in Complex with Heme and Azide.
Overview
Heme oxygenase (HO) catalyzes physiological heme degradation consisting of three sequential oxidation steps that use dioxygen molecules and reducing equivalents. We determined the crystal structure of rat HO-1 in complex with heme and azide (HO-heme-N(3)(-)) at 1.9-A resolution. The azide, whose terminal nitrogen atom is coordinated to the ferric heme iron, is situated nearly parallel to the heme plane, and its other end is directed toward the alpha-meso position of the heme. Based on resonance Raman spectroscopic analysis of HO-heme bound to dioxygen, this parallel coordination mode suggests that the azide is an analog of dioxygen. The azide is surrounded by residues of the distal F-helix with only the direction to the alpha-meso carbon being open. This indicates that regiospecific oxygenation of the heme is primarily caused by the steric constraint between the dioxygen bound to heme and the F-helix. The azide interacts with Asp-140, Arg-136, and Thr-135 through a hydrogen bond network involving five water molecules on the distal side of the heme. This network, also present in HO-heme, may function in dioxygen activation in the first hydroxylation step. From the orientation of azide in HO-heme-N(3)(-), the dioxygen or hydroperoxide bound to HO-heme, the active oxygen species of the first reaction, is inferred to have a similar orientation suitable for a direct attack on the alpha-meso carbon.
About this Structure
1IVJ is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
Crystal structure of rat heme oxygenase-1 in complex with heme bound to azide. Implication for regiospecific hydroxylation of heme at the alpha-meso carbon., Sugishima M, Sakamoto H, Higashimoto Y, Omata Y, Hayashi S, Noguchi M, Fukuyama K, J Biol Chem. 2002 Nov 22;277(47):45086-90. Epub 2002 Sep 15. PMID:12235152 Page seeded by OCA on Fri May 2 20:28:18 2008
