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1kok
From Proteopedia
(New page: 200px<br /><applet load="1kok" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kok, resolution 1.70Å" /> '''Crystal Structure of...) |
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| - | [[Image:1kok.gif|left|200px]]<br /><applet load="1kok" size=" | + | [[Image:1kok.gif|left|200px]]<br /><applet load="1kok" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1kok, resolution 1.70Å" /> | caption="1kok, resolution 1.70Å" /> | ||
'''Crystal Structure of Mesopone Cytochrome c Peroxidase (MpCcP)'''<br /> | '''Crystal Structure of Mesopone Cytochrome c Peroxidase (MpCcP)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The effect of heme ring oxygenation on enzyme structure and function has | + | 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== | ==About this Structure== | ||
| - | 1KOK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with HIF as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cytochrome-c_peroxidase Cytochrome-c peroxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.5 1.11.1.5] Full crystallographic information is available from [http:// | + | 1KOK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=HIF:'>HIF</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cytochrome-c_peroxidase Cytochrome-c peroxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.5 1.11.1.5] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KOK OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Saccharomyces cerevisiae]] | [[Category: Saccharomyces cerevisiae]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Barrows, T | + | [[Category: Barrows, T P.]] |
[[Category: Bhaskar, B.]] | [[Category: Bhaskar, B.]] | ||
| - | [[Category: Cohen, M | + | [[Category: Cohen, M S.]] |
| - | [[Category: Farmer, P | + | [[Category: Farmer, P J.]] |
| - | [[Category: Immoos, C | + | [[Category: Immoos, C E.]] |
| - | [[Category: Poulos, T | + | [[Category: Poulos, T L.]] |
[[Category: HIF]] | [[Category: HIF]] | ||
[[Category: bifunctional catalyst]] | [[Category: bifunctional catalyst]] | ||
| Line 29: | Line 29: | ||
[[Category: trp191 cationic radical]] | [[Category: trp191 cationic radical]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:36:18 2008'' |
Revision as of 11:36, 21 February 2008
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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 with as ligand. Active as Cytochrome-c peroxidase, with EC number 1.11.1.5 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 Thu Feb 21 13:36:18 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. | HIF | Bifunctional catalyst | Cytochrome c peroxidase | Cytochrome oxidase | Mesoporphyrin | Nitrite reducatse | Proximal loop | Trp191 cationic radical
