1kok
From Proteopedia
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[[Image:1kok.gif|left|200px]] | [[Image:1kok.gif|left|200px]] | ||
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'''Crystal Structure of Mesopone Cytochrome c Peroxidase (MpCcP)''' | '''Crystal Structure of Mesopone Cytochrome c Peroxidase (MpCcP)''' | ||
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[[Category: Immoos, C E.]] | [[Category: Immoos, C E.]] | ||
[[Category: Poulos, T L.]] | [[Category: Poulos, T L.]] | ||
- | [[Category: | + | [[Category: Bifunctional catalyst]] |
- | [[Category: | + | [[Category: Cytochrome c peroxidase]] |
- | [[Category: | + | [[Category: Cytochrome oxidase]] |
- | [[Category: | + | [[Category: Mesoporphyrin]] |
- | [[Category: | + | [[Category: Nitrite reducatse]] |
- | [[Category: | + | [[Category: Proximal loop]] |
- | [[Category: | + | [[Category: Trp191 cationic radical]] |
- | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:59:15 2008'' | |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + |
Revision as of 19:59, 2 May 2008
Crystal Structure of Mesopone Cytochrome c Peroxidase (MpCcP)
Overview
The effect of heme ring oxygenation on enzyme structure and function has been examined in a reconstituted cytochrome c peroxidase. Oxochlorin derivatives were formed by OsO(4) treatment of mesoporphyrin followed by acid-catalyzed pinacol rearrangement. The northern oxochlorin isomers were isolated by chromatography, and the regio-isomers assignments determined by 2D COSY and NOE 1H NMR. The major isomer, 4-mesoporphyrinone (Mp), was metallated with FeCl(2) and reconstituted into cytochrome c peroxidase (CcP) forming a hybrid green protein, MpCcP. The heme-altered enzyme has 99% wild-type peroxidase activity with cytochrome c. EPR spectroscopy of MpCcP intermediate compound I verifies the formation of the Trp(191) radical similar to wild-type CcP in the reaction cycle. Peroxidase activity with small molecules is varied: guaiacol turnover increases approximately five-fold while that with ferrocyanide is approximately 85% of native. The electron-withdrawing oxo-substitutents on the cofactor cause a approximately 60-mV increase in Fe(III)/Fe(II) reduction potential. The present investigation represents the first structural characterization of an oxochlorin protein with X-ray intensity data collected to 1.70 A. Although a mixture of R- and S-mesopone isomers of the FeMP cofactor was used during heme incorporation into the apo-protein, only the S-isomer is found in the crystallized protein.
About this Structure
1KOK is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Mesopone cytochrome c peroxidase: functional model of heme oxygenated oxidases., Immoos CE, Bhaskar B, Cohen MS, Barrows TP, Farmer PJ, Poulos TL, J Inorg Biochem. 2002 Sep 20;91(4):635-43. PMID:12237229 Page seeded by OCA on Fri May 2 22:59:15 2008
Categories: Cytochrome-c peroxidase | Saccharomyces cerevisiae | Single protein | Barrows, T P. | Bhaskar, B. | Cohen, M S. | Farmer, P J. | Immoos, C E. | Poulos, T L. | Bifunctional catalyst | Cytochrome c peroxidase | Cytochrome oxidase | Mesoporphyrin | Nitrite reducatse | Proximal loop | Trp191 cationic radical