The structure of the 2[4Fe-4S] ferredoxin from Pseudomonas aeruginosa at 1.32-A resolution: comparison with other high-resolution structures of ferredoxins and contributing structural features to reduction potential values.
The structure of the 2[4Fe-4S] ferredoxin (PaFd) from Pseudomonas aeruginosa, which belongs to the Allochromatium vinosum (Alvin) subfamily, has been determined by X-ray crystallography at 1.32-A resolution, which is the highest up to now for a member of this subfamily of Fds. The main structural features of PaFd are similar to those of AlvinFd. However, the significantly higher resolution of the PaFd structure makes possible a reliable comparison with available high-resolution structures of [4Fe-4S]-containing Fds, in an effort to rationalize the unusual electrochemical properties of Alvin-like Fds. Three major factors contributing to the reduction potential values of [4Fe-4S]2+/+ clusters of Fds, namely, the surface accessibility of the clusters, the N-H...S hydrogen-bonding network, and the volume of the cavities hosting the clusters, are extensively discussed. The volume of the cavities is introduced in the present work for the first time, and can in part explain the very negative potential of cluster I of Alvin-like Fds.
Giastas
Petros
P
Institute of Physical Chemistry, NCSR Demokritos, Aghia Paraskevi, 15310, PO Box 60228, Athens, Greece.
Pinotsis
Nikos
N
Efthymiou
Georgios
G
Wilmanns
Matthias
M
Kyritsis
Panayotis
P
Moulis
Jean-Marc
JM
Mavridis
Irene M
IM
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D005288:Ferredoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006860:Hydrogen Bonding; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D017434:Protein Structure, Tertiary; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014961:X-Ray Diffraction
D001426:Bacterial Proteins; D005288:Ferredoxins; D007506:Iron-Sulfur Proteins