1ff2
From Proteopedia
(New page: 200px<br /><applet load="1ff2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ff2, resolution 2.30Å" /> '''CRYSTAL STRUCTURE OF...) |
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| - | [[Image:1ff2.jpg|left|200px]]<br /><applet load="1ff2" size=" | + | [[Image:1ff2.jpg|left|200px]]<br /><applet load="1ff2" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ff2, resolution 2.30Å" /> | caption="1ff2, resolution 2.30Å" /> | ||
'''CRYSTAL STRUCTURE OF THE C42D MUTANT OF AZOTOBACTER VINELANDII 7FE FERREDOXIN (FDI)'''<br /> | '''CRYSTAL STRUCTURE OF THE C42D MUTANT OF AZOTOBACTER VINELANDII 7FE FERREDOXIN (FDI)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | All naturally occurring ferredoxins that have Cys-X-X-Asp-X-X-Cys motifs | + | All naturally occurring ferredoxins that have Cys-X-X-Asp-X-X-Cys motifs contain [4Fe-4S](2+/+) clusters that can be easily and reversibly converted to [3Fe-4S](+/0) clusters. In contrast, ferredoxins with unmodified Cys-X-X-Cys-X-X-Cys motifs assemble [4Fe-4S](2+/+) clusters that cannot be easily interconverted with [3Fe-4S](+/0) clusters. In this study we changed the central cysteine of the Cys(39)-X-X-Cys(42)-X-X-Cys(45) of Azotobacter vinelandii FdI, which coordinates its [4Fe-4S](2+/+) cluster, into an aspartate. UV-visible, EPR, and CD spectroscopies, metal analysis, and x-ray crystallography show that, like native FdI, aerobically purified C42D FdI is a seven-iron protein retaining its [4Fe-4S](2+/+) cluster with monodentate aspartate ligation to one iron. Unlike known clusters of this type the reduced [4Fe-4S](+) cluster of C42D FdI exhibits only an S = 1/2 EPR with no higher spin signals detected. The cluster shows only a minor change in reduction potential relative to the native protein. All attempts to convert the cluster to a 3Fe cluster using conventional methods of oxygen or ferricyanide oxidation or thiol exchange were not successful. The cluster conversion was ultimately accomplished using a new electrochemical method. Hydrophobic and electrostatic interaction and the lack of Gly residues adjacent to the Asp ligand explain the remarkable stability of this cluster. |
==About this Structure== | ==About this Structure== | ||
| - | 1FF2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Azotobacter_vinelandii Azotobacter vinelandii] with SF4 and F3S as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1FF2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Azotobacter_vinelandii Azotobacter vinelandii] with <scene name='pdbligand=SF4:'>SF4</scene> and <scene name='pdbligand=F3S:'>F3S</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FF2 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Azotobacter vinelandii]] | [[Category: Azotobacter vinelandii]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Burgess, B | + | [[Category: Burgess, B K.]] |
| - | [[Category: Stout, C | + | [[Category: Stout, C D.]] |
[[Category: F3S]] | [[Category: F3S]] | ||
[[Category: SF4]] | [[Category: SF4]] | ||
[[Category: 7fe ferredoxin]] | [[Category: 7fe ferredoxin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:38:01 2008'' |
Revision as of 10:38, 21 February 2008
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CRYSTAL STRUCTURE OF THE C42D MUTANT OF AZOTOBACTER VINELANDII 7FE FERREDOXIN (FDI)
Overview
All naturally occurring ferredoxins that have Cys-X-X-Asp-X-X-Cys motifs contain [4Fe-4S](2+/+) clusters that can be easily and reversibly converted to [3Fe-4S](+/0) clusters. In contrast, ferredoxins with unmodified Cys-X-X-Cys-X-X-Cys motifs assemble [4Fe-4S](2+/+) clusters that cannot be easily interconverted with [3Fe-4S](+/0) clusters. In this study we changed the central cysteine of the Cys(39)-X-X-Cys(42)-X-X-Cys(45) of Azotobacter vinelandii FdI, which coordinates its [4Fe-4S](2+/+) cluster, into an aspartate. UV-visible, EPR, and CD spectroscopies, metal analysis, and x-ray crystallography show that, like native FdI, aerobically purified C42D FdI is a seven-iron protein retaining its [4Fe-4S](2+/+) cluster with monodentate aspartate ligation to one iron. Unlike known clusters of this type the reduced [4Fe-4S](+) cluster of C42D FdI exhibits only an S = 1/2 EPR with no higher spin signals detected. The cluster shows only a minor change in reduction potential relative to the native protein. All attempts to convert the cluster to a 3Fe cluster using conventional methods of oxygen or ferricyanide oxidation or thiol exchange were not successful. The cluster conversion was ultimately accomplished using a new electrochemical method. Hydrophobic and electrostatic interaction and the lack of Gly residues adjacent to the Asp ligand explain the remarkable stability of this cluster.
About this Structure
1FF2 is a Single protein structure of sequence from Azotobacter vinelandii with and as ligands. Full crystallographic information is available from OCA.
Reference
Structure of C42D Azotobacter vinelandii FdI. A Cys-X-X-Asp-X-X-Cys motif ligates an air-stable [4Fe-4S]2+/+ cluster., Jung YS, Bonagura CA, Tilley GJ, Gao-Sheridan HS, Armstrong FA, Stout CD, Burgess BK, J Biol Chem. 2000 Nov 24;275(47):36974-83. PMID:10961993
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