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| {{STRUCTURE_2iqf| PDB=2iqf | SCENE= }} | | {{STRUCTURE_2iqf| PDB=2iqf | SCENE= }} |
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- | '''Crystal structure of Helicobacter pylori catalase compound I'''
| + | ===Crystal structure of Helicobacter pylori catalase compound I=== |
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- | ==Overview==
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- | The structures of Helicobacter pylori (HPC) and Penicillium vitale (PVC) catalases, each with two subunits in the crystal asymmetric unit, oxidized with peroxoacetic acid are reported at 1.8 and 1.7 A resolution, respectively. Despite the similar oxidation conditions employed, the iron-oxygen coordination length is 1.72 A for PVC, close to what is expected for a Fe=O double bond, and 1.80 and 1.85 A for HPC, suggestive of a Fe-O single bond. The structure and electronic configuration of the oxoferryl heme and immediate protein environment is investigated further by QM/MM density functional theory calculations. Four different active site electronic configurations are considered, Por*+-FeIV=O, Por*+-FeIV=O...HisH+, Por*+-FeIV-OH+ and Por-FeIV-OH (a protein radical is assumed in the latter configuration). The electronic structure of the primary oxidized species, Por*+-FeIV=O, differs qualitatively between HPC and PVC with an A2u-like porphyrin radical delocalized on the porphyrin in HPC and a mixed A1u-like "fluctuating" radical partially delocalized over the essential distal histidine, the porphyrin, and, to a lesser extent, the proximal tyrosine residue. This difference is rationalized in terms of HPC containing heme b and PVC containing heme d. It is concluded that compound I of PVC contains an oxoferryl Por*+-FeIV=O species with partial protonation of the distal histidine and compound I of HPC contains a hydroxoferryl Por-FeIV-OH with the second oxidation equivalent delocalized as a protein radical. The findings support the idea that there is a relation between radical migration to the protein and protonation of the oxoferryl bond in catalase. | + | The line below this paragraph, {{ABSTRACT_PUBMED_17358056}}, adds the Publication Abstract to the page |
| + | (as it appears on PubMed at http://www.pubmed.gov), where 17358056 is the PubMed ID number. |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Hydroxoferryl heme]] | | [[Category: Hydroxoferryl heme]] |
| [[Category: Oxidoreductase]] | | [[Category: Oxidoreductase]] |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 07:46:26 2008'' | + | |
| + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 20:41:54 2008'' |
Revision as of 17:41, 27 July 2008
Template:STRUCTURE 2iqf
Crystal structure of Helicobacter pylori catalase compound I
Template:ABSTRACT PUBMED 17358056
About this Structure
2IQF is a Single protein structure of sequence from Helicobacter pylori. Full crystallographic information is available from OCA.
Reference
The structures and electronic configuration of compound I intermediates of Helicobacter pylori and Penicillium vitale catalases determined by X-ray crystallography and QM/MM density functional theory calculations., Alfonso-Prieto M, Borovik A, Carpena X, Murshudov G, Melik-Adamyan W, Fita I, Rovira C, Loewen PC, J Am Chem Soc. 2007 Apr 11;129(14):4193-205. Epub 2007 Mar 15. PMID:17358056
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