title: Flavodoxin: a compromise between efficiency and versatility in the electron transfer from Photosystem I to Ferredoxin-NADP(+) reductase.
abstract: Under iron-deficient conditions Flavodoxin (Fld) replaces Ferredoxin in Anabaena as electron carrier from Photosystem I (PSI) to Ferredoxin-NADP(+) reductase (FNR). Several residues modulate the Fld interaction with FNR and PSI, but no one appears as specifically critical for efficient electron transfer (ET). Fld shows a strong dipole moment, with its negative end directed towards the flavin ring. The role of this dipole moment in the processes of interaction and ET with positively charged surfaces exhibited by PSI and FNR has been analysed by introducing single and multiple charge reversal mutations on the Fld surface. Our data confirm that in this system interactions do not rely on a precise complementary surface of the reacting molecules. In fact, they indicate that the initial orientation driven by the alignment of dipole moment of the Fld molecule with that of the partner contributes to the formation of a bunch of alternative binding modes competent for the efficient ET reaction. Additionally, the fact that Fld uses different interaction surfaces to dock to PSI and to FNR is confirmed.
authors.affiliation: Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009-Zaragoza, Spain.
authors.forename: Guillermina
authors.initials: G
authors.lastname: Goñi
authors.forename: Beatriz
authors.initials: B
authors.lastname: Herguedas
authors.forename: Manuel
authors.initials: M
authors.lastname: Hervás
authors.forename: José R
authors.initials: JR
authors.lastname: Peregrina
authors.forename: Miguel A
authors.initials: MA
authors.lastname: De la Rosa
authors.forename: Carlos
authors.initials: C
authors.lastname: Gómez-Moreno
authors.forename: José A
authors.initials: JA
authors.lastname: Navarro
authors.forename: Juan A
authors.initials: JA
authors.lastname: Hermoso
authors.forename: Marta
authors.initials: M
authors.lastname: Martínez-Júlvez
authors.forename: Milagros
authors.initials: M
authors.lastname: Medina
mesh_terms: D017033:Anabaena / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004579:Electron Transport / Q000502:physiology; D005287:Ferredoxin-NADP Reductase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005418:Flavodoxin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D045331:Photosystem I Protein Complex / Q000737:chemistry* / Q000378:metabolism; D055672:Static Electricity
chemical_list: D005418:Flavodoxin; D045331:Photosystem I Protein Complex; D009249:NADP; D005287:Ferredoxin-NADP Reductase