1gem
From Proteopedia
(New page: 200px<br /><applet load="1gem" size="450" color="white" frame="true" align="right" spinBox="true" caption="1gem, resolution 2.0Å" /> '''STRUCTURAL CHARACTERI...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1gem.jpg|left|200px]]<br /><applet load="1gem" size=" | + | [[Image:1gem.jpg|left|200px]]<br /><applet load="1gem" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1gem, resolution 2.0Å" /> | caption="1gem, resolution 2.0Å" /> | ||
'''STRUCTURAL CHARACTERIZATION OF N-BUTYL-ISOCYANIDE COMPLEXES OF CYTOCHROMES P450NOR AND P450CAM'''<br /> | '''STRUCTURAL CHARACTERIZATION OF N-BUTYL-ISOCYANIDE COMPLEXES OF CYTOCHROMES P450NOR AND P450CAM'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Alkyl-isocyanides are able to bind to both ferric and ferrous iron of the | + | Alkyl-isocyanides are able to bind to both ferric and ferrous iron of the heme in cytochrome P450, and the resulting complexes exhibit characteristic optical absorption spectra. While the ferric complex gives a single Soret band at 430 nm, the ferrous complex shows double Soret bands at 430 and 450 nm. The ratio of intensities of the double Soret bands in the ferrous isocyanide complex of P450 varies, as a function of pH, ionic strength, and the origin of the enzyme. To understand the structural origin of these characteristic spectral features, we examined the crystallographic and spectrophotometric properties of the isocyanide complexes of Pseudomonas putida cytochrome P450cam and Fusarium oxysporum cytochorme P450nor, since ferrous isocyanide complex of P450cam gives a single Soret band at 453 nm, while that of P450nor gives one at 427 nm. Corresponding to the optical spectra, we observed C-N stretching of a ferrous iron-bound isocyanide at 2145 and 2116 cm(-1) for P450nor and P450cam, respectively. The crystal structures of the ferric and ferrous n-butyl isocyanide complexes of P450cam and P450nor were determined. The coordination structure of the fifth Cys thiolate was indistinguishable for the two P450s, but the coordination geometry of the isocyanide was different for the case of P450cam [d(Fe-C) = 1.86 A, angleFe-C-N = 159 degrees ] versus P450nor [d(Fe-C) = 1.85 A, angleFe-C-N = 175 degrees ]. Another difference in the structures was the chemical environment of the heme pocket. In the case of P450cam, the iron-bound isocyanide is surrounded by some hydrophobic side chains, while, for P450nor, it is surrounded by polar groups including several water molecules. On the basis of these observations, we proposed that the steric factors and/or the polarity of the environment surrounding the iron-bound isocyanide significantly effect on the resonance structure of the heme(Fe)-isocyanide moiety and that differences in these two factors are responsible for the spectral characteristics for P450s. |
==About this Structure== | ==About this Structure== | ||
| - | 1GEM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida] with HEM and NBN as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Camphor_5-monooxygenase Camphor 5-monooxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.15.1 1.14.15.1] Full crystallographic information is available from [http:// | + | 1GEM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=NBN:'>NBN</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Camphor_5-monooxygenase Camphor 5-monooxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.15.1 1.14.15.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GEM OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Pseudomonas putida]] | [[Category: Pseudomonas putida]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Lee, D | + | [[Category: Lee, D S.]] |
| - | [[Category: Park, S | + | [[Category: Park, S Y.]] |
[[Category: Shiro, Y.]] | [[Category: Shiro, Y.]] | ||
[[Category: Yamane, K.]] | [[Category: Yamane, K.]] | ||
| Line 24: | Line 24: | ||
[[Category: x-ray crystallography]] | [[Category: x-ray crystallography]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:49:13 2008'' |
Revision as of 10:49, 21 February 2008
|
STRUCTURAL CHARACTERIZATION OF N-BUTYL-ISOCYANIDE COMPLEXES OF CYTOCHROMES P450NOR AND P450CAM
Overview
Alkyl-isocyanides are able to bind to both ferric and ferrous iron of the heme in cytochrome P450, and the resulting complexes exhibit characteristic optical absorption spectra. While the ferric complex gives a single Soret band at 430 nm, the ferrous complex shows double Soret bands at 430 and 450 nm. The ratio of intensities of the double Soret bands in the ferrous isocyanide complex of P450 varies, as a function of pH, ionic strength, and the origin of the enzyme. To understand the structural origin of these characteristic spectral features, we examined the crystallographic and spectrophotometric properties of the isocyanide complexes of Pseudomonas putida cytochrome P450cam and Fusarium oxysporum cytochorme P450nor, since ferrous isocyanide complex of P450cam gives a single Soret band at 453 nm, while that of P450nor gives one at 427 nm. Corresponding to the optical spectra, we observed C-N stretching of a ferrous iron-bound isocyanide at 2145 and 2116 cm(-1) for P450nor and P450cam, respectively. The crystal structures of the ferric and ferrous n-butyl isocyanide complexes of P450cam and P450nor were determined. The coordination structure of the fifth Cys thiolate was indistinguishable for the two P450s, but the coordination geometry of the isocyanide was different for the case of P450cam [d(Fe-C) = 1.86 A, angleFe-C-N = 159 degrees ] versus P450nor [d(Fe-C) = 1.85 A, angleFe-C-N = 175 degrees ]. Another difference in the structures was the chemical environment of the heme pocket. In the case of P450cam, the iron-bound isocyanide is surrounded by some hydrophobic side chains, while, for P450nor, it is surrounded by polar groups including several water molecules. On the basis of these observations, we proposed that the steric factors and/or the polarity of the environment surrounding the iron-bound isocyanide significantly effect on the resonance structure of the heme(Fe)-isocyanide moiety and that differences in these two factors are responsible for the spectral characteristics for P450s.
About this Structure
1GEM is a Single protein structure of sequence from Pseudomonas putida with and as ligands. Active as Camphor 5-monooxygenase, with EC number 1.14.15.1 Full crystallographic information is available from OCA.
Reference
Structural characterization of n-butyl-isocyanide complexes of cytochromes P450nor and P450cam., Lee DS, Park SY, Yamane K, Obayashi E, Hori H, Shiro Y, Biochemistry. 2001 Mar 6;40(9):2669-77. PMID:11258878
Page seeded by OCA on Thu Feb 21 12:49:13 2008
