English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/28478
Share/Impact:
Statistics
logo share SHARE   Add this article to your Mendeley library MendeleyBASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Title

Characterization of the cross-linked complex formed between ferredoxin-NADP+ reductase and flavodoxin from Anabaena PCC 7119

AuthorsPueyo, José Javier ; Gómez-Moreno, Carlos
KeywordsCross-linking
Electron transfer
Photosynthetic particle
Ferredoxin
Flavoprotein
Cyanobacterium
Anabaena PCC 7119
Issue Date1991
PublisherElsevier
CitationBiochimica et Biophysica Acta 1059: 149-156 (1991)
AbstractA covalent complex between ferredoxin-NADP ÷ reductase and fiavodoxin, two flavoproteins isolated from the nitrogen-fixing cyanobacterium Anabaena, has been formed by a cross-linking reaction with a water-soluble carbodiimide. The complex has a 1 : 1 stoichiometry and an absorption spectrum similar to that of the mixture of the free proteins. Both proteins can be detected immunochemically when they are in the complex, since they react with antisera raised against the isolated proteins. The complex is shown to be active in the NADPH-cytochrome c reductase reaction, although with a lower turnover number than FNR when ferredoxin is used as the electron carrier. Stopped-flow experiments have shown a lower rate of electron transfer (approx. 20-fold) from the semiquinone form of flavodoxin, when bound into the complex, to cytochrome c, as compared to the free protein. Anaerobic titration of the reduced complex with NADP + also indicates that there is transfer of electrons between the reductase and flavodoxin in the complex. Nevertheless, the covalent complex is found to be unable by itself to mediate the transfer of electrons from photosynthetic particles to NADP +. This indicates that the pathway for the entrance of electrons into the complex is partially or completely blocked depending on the degree of cross-linkage. However, some activity is shown when ferredoxin is added to the system. The covalent complex shows a limited ability to act as an electron transfer protein between photosynthetic membranes and either exogenous FNR or cytochrome c. The concentration of complex required in this case is also much higher than when free ferredoxin or flavodoxin are present. It is concluded that the covalent complex formed by ferredoxin-NADP + reductase and flavodoxin from the cyanobacterium Anabaena PCC 7119 can be used as a simplified model for the study of electron transfer reactions between two flavoproteins. It can not be used for the study of reactions involving reduction of NADP ÷ by photosynthetic particles.
Description7 pages, figures, and tables statistics.
URIhttp://hdl.handle.net/10261/28478
ISSN0005-2728
Appears in Collections:(IRN) Artículos
Files in This Item:
There are no files associated with this item.
Show full item record
Review this work
 


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.