Role of critical charged residues in reduction potential modulation of ferredoxin-NADP+ reductase.
Reduction potential determinations of K75E, E139K and E301A ferredoxin-NADP+ reductases provide valuable information concerning the factors that contribute to tune the flavin reduction potential. Thus, while E139 is not involved in such modulation, the K75 side-chain tunes the flavin potential by creating a defined environment that modulates the FAD conformation. Finally, the E301 side-chain influences not only the flavin reduction potential, but also the electron transfer mechanism, as suggested from the values determined for the E301A mutant, where E(ox/rd) and E(sq/rd) shifted +41 and +102 mV, respectively, with regard to wild-type. Reduction potentials allowed estimation of binding energies differences of the FAD cofactor upon reduction.
Faro
Merche
M
Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Spain.
Gómez-Moreno
Carlos
C
Stankovich
Marian
M
Medina
Milagros
M
D000596:Amino Acids / Q000378:metabolism*; D017033:Anabaena / Q000378:metabolism; D005287:Ferredoxin-NADP Reductase / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction
D000596:Amino Acids; D005287:Ferredoxin-NADP Reductase