Influence of surface charges on redox properties in high potential iron-sulfur proteins.
The pH-dependence of the reduction potential determined through differential pulse voltammetry for the high potential iron sulfur proteins (HiPIP) from R. globiformis, C. vinosum, R. gelatinosus, E. vacuolata (I and II), E. halophila (I and II) is reported. A decrease in reduction potential with pH is invariably observed in the pH range where deprotonation of the imidazolium nitrogen of histidine residue(s) occurs. No pH dependence is observed for the only protein lacking histidines. It appears that surface charges like the His imidazolium groups are capable of influencing the reduction potential despite the known quencing of the electrostatic interactions due to solvent effects.
Luchinat
C
C
Institute of Agricultural Chemistry, University of Bologna, Italy.
Capozzi
F
F
Borsari
M
M
Battistuzzi
G
G
Sola
M
M
D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D010084:Oxidation-Reduction; D045322:Photosynthetic Reaction Center Complex Proteins; D013045:Species Specificity; D013499:Surface Properties
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; C007943:high potential iron-sulfur protein