1FF2
CRYSTAL STRUCTURE OF THE C42D MUTANT OF AZOTOBACTER VINELANDII 7FE FERREDOXIN (FDI)
Summary for 1FF2
| Entry DOI | 10.2210/pdb1ff2/pdb |
| Related | 6FD1 |
| Descriptor | FERREDOXIN I, IRON/SULFUR CLUSTER, FE3-S4 CLUSTER, ... (4 entities in total) |
| Functional Keywords | 7fe ferredoxin, electron transport |
| Biological source | Azotobacter vinelandii |
| Total number of polymer chains | 1 |
| Total formula weight | 12718.91 |
| Authors | Stout, C.D.,Burgess, B.K. (deposition date: 2000-07-24, release date: 2000-08-21, Last modification date: 2024-02-07) |
| Primary citation | Jung, Y.S.,Bonagura, C.A.,Tilley, G.J.,Gao-Sheridan, H.S.,Armstrong, F.A.,Stout, C.D.,Burgess, B.K. Structure of C42D Azotobacter vinelandii FdI. A Cys-X-X-Asp-X-X-Cys motif ligates an air-stable [4Fe-4S]2+/+ cluster J.Biol.Chem., 275:36974-36983, 2000 Cited by PubMed Abstract: 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. PubMed: 10961993DOI: 10.1074/jbc.M004947200 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.3 Å) |
Structure validation
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