Electron Transfer from the Bound Iron–Sulfur Clusters to Ferredoxin/Flavodoxin: Kinetic and Structural Properties of Ferredoxin/Flavodoxin Reduction by Photosystem I

Photosynthetic fuel for heterologous enzymes: the role of electron carrier proteins

“…Ferredoxin-FNR and ferredoxin-photosystem I interactions have been studied extensively through structural and kinetic techniques coupled with site-specific mutagenesis and involve prominent contributions from electrostatic interactions ( Fig. 1) (Hurley et al 2006;Sétif 2006).…”

“…That said, some enzymes, e.g., diflavin reductases, possess FMN-binding domains structurally homologous to flavodoxins (Medina 2009), and the flavodoxin fold, like the ferredoxin fold, is ancient and figures among the nine most ancient protein folds (Caetano-Anollés et al 2007). Despite the fact that flavodoxin and ferredoxin share no sequence or structural homology, they possess many common biochemical characteristics, namely low isoelectric points, comparable redox potentials, and similar electron transfer kinetics towards both photosystem I and FNR (Bottin and Lagoutte 1992;Hurley et al 2006;Sétif 2006;Goñi et al 2008Goñi et al , 2009. Their electrostatic surface potentials can be closely aligned, which suggests that much of their functional equivalence stems from similar means of interaction ( Fig.…”

“…2b) (Crowley and Ubbink 2003). These effects are key to ensure rapid electron transfer and lead to a characteristic bell-shaped dependence of electron transfer rates on ionic strength (Sétif 2006). Because electrostatic surfaces play such prominent roles in determining the connectivity of electron transfer proteins ( Fig.…”

Fast Kinetic Methods with Photodiode Array Detection in the Study of the Interaction and Electron Transfer Between Flavodoxin and Ferredoxin NADP+-Reductase

“…During Fld-dependent photosynthetic ET the Fld molecule must pivot between its docking sites in PSI and in FNR. Formation of transient complexes of Fld with FNR in vivo is useful during this process, though not critical, for promoting efficient reduction of Fld and FNR and for avoiding reduction of oxygen by the donor redox centres (Goñi et al, 2008;Goñi et al, 2009;Hurley et al, 2006;Sétif, 2001Sétif, , 2006 Despite the high similarity among the spectra for the same redox states within both proteins, the methodology here used allowed identifying the composition of the intermediate species and final species of the reactions, as long as the kinetics fits in the measurable instrumental time. The mechanism of these inter-flavin ET reactions is revisited, evaluating the evolution of the reaction along the time within a wavelength spectral range by using a PDA detector.…”

Computer Simulation of Protein-Protein Association in Photosynthesis

“…It is widely recognized that electrostatic interactions play a crucial role in the binding of Pc and Fd to their reaction partners [9,28]: they govern the diffusion of a mobile protein to its docking sites at protein complexes orienting a mobile molecule in the electrostatic field and thus influencing an association rate.…”