Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119

8 pages, figures, and tables statistics.

Detalles Bibliográficos
Autores: Walker, Mark C., Pueyo, José Javier, Gómez-Moreno, Carlos
Tipo de recurso: artículo
Fecha de publicación:1990
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/26062
Acceso en línea:http://hdl.handle.net/10261/26062
Access Level:acceso abierto
Palabra clave:Intramolecular Electron Transfer
Electro Transfer in Electrostatic
Covalent complexes
Ferredoxin-NADP+
Reductase and Flavodoxin
Anabaena PCC 7119
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spelling Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119Walker, Mark C.Pueyo, José JavierGómez-Moreno, CarlosIntramolecular Electron TransferElectro Transfer in ElectrostaticCovalent complexesFerredoxin-NADP+Reductase and FlavodoxinAnabaena PCC 71198 pages, figures, and tables statistics.The kinetics of reduction and intracomplex electron transfer in electrostatically stabilized and covalently crosslinked complexes between ferredoxin-NADP+ reductase (FNR) and flavodoxin (Fld) from the cyanobacterium Anabuena PCC 7119 were compared using laser flash photolysis. The second-order rate constant for reduction by 5-deazariboflavin semiquinone (dRfII) of FNR within the electrostatically stabilized complex at 10 mM ionic strength (4.0 X 10s M-’ s-‘) was identical to that for free FNR. This suggests that the FAD cofactor of FNR is not sterically hindered upon complex formation. A lower limit of approximately 7000 s-l was estimated for the first-order rate constant for intracomplex electron transfer from FNRmd to Fl&, under these conditions. In contrast, for the covalently crosslinked complex, a smaller secondorder rate constant (2.1 X lo* M-’ s-l) was obtained for the reduction of FNR by dRfII within the complex, suggesting that some steric hindrance of the FAD cofactor of FNR occurs due to crosslinking. A limiting rate constant of 1000 s-l for the intracomplex electron transfer reaction was obtained for the covalent complex, which was unaffected by changes in ionic strength. The substantially diminished limiting rate constant, relative to that of the electrostatic complex, may reflect either a suboptimal orientation of the redox cofactors within the covalent complex or a required structural reorganization preceding electron transfer which is not allowed once the proteins have been covalently linked. Thus, although the covalent complex is biochemically competent, it is not a quantitatively precise model for the catalytically relevant intermediate along the reaction pathway.This work was supported in part by Grant DK15057 from the National Institutes of Health (to G.T.) and Grant 0792/84 from the Comision Asesora de Investigation Cientifica y Tecnica, Spain (to C.G.-M.).Peer reviewedAcademic Press201020101990info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_65011057069 bytesapplication/pdfhttp://hdl.handle.net/10261/26062reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglésinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/260622026-05-22T06:33:51Z
dc.title.none.fl_str_mv Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119
title Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119
spellingShingle Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119
Walker, Mark C.
Intramolecular Electron Transfer
Electro Transfer in Electrostatic
Covalent complexes
Ferredoxin-NADP+
Reductase and Flavodoxin
Anabaena PCC 7119
title_short Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119
title_full Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119
title_fullStr Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119
title_full_unstemmed Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119
title_sort Comparison of the Kinetics of Reduction and Intramolecular Electron Transfer in Electrostatic and Covalent Complexes of Ferredoxin-NADP+ Reductase and Flavodoxin from Anabaena PCC 7119
dc.creator.none.fl_str_mv Walker, Mark C.
Pueyo, José Javier
Gómez-Moreno, Carlos
author Walker, Mark C.
author_facet Walker, Mark C.
Pueyo, José Javier
Gómez-Moreno, Carlos
author_role author
author2 Pueyo, José Javier
Gómez-Moreno, Carlos
author2_role author
author
dc.subject.none.fl_str_mv Intramolecular Electron Transfer
Electro Transfer in Electrostatic
Covalent complexes
Ferredoxin-NADP+
Reductase and Flavodoxin
Anabaena PCC 7119
topic Intramolecular Electron Transfer
Electro Transfer in Electrostatic
Covalent complexes
Ferredoxin-NADP+
Reductase and Flavodoxin
Anabaena PCC 7119
description 8 pages, figures, and tables statistics.
publishDate 1990
dc.date.none.fl_str_mv 1990
2010
2010
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/26062
url http://hdl.handle.net/10261/26062
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 1057069 bytes
application/pdf
dc.publisher.none.fl_str_mv Academic Press
publisher.none.fl_str_mv Academic Press
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
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