Mechanism of Coenzyme Recognition and Binding Revealed by Crystal Structure Analysis of Ferredoxin–NADP+ Reductase Complexed with NADP+
| Autor: | Milagros Medina, Tomás Mayoral, Carlos Gómez-Moreno, Julia Sanz-Aparicio, Merche Faro, Juan A. Hermoso |
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| Rok vydání: | 2002 |
| Předmět: |
Models
Molecular inorganic chemicals Stereochemistry Electrons Crystallography X-Ray environment and public health Protein Structure Secondary Cofactor Substrate Specificity Electron Transport Structural Biology Oxidoreductase Coenzyme binding Molecular Biology Ternary complex Ferredoxin Nicotinamide mononucleotide chemistry.chemical_classification biology Chemistry Anabaena Ferredoxin-NADP Reductase enzymes and coenzymes (carbohydrates) Crystallography biology.protein bacteria NAD+ kinase NADP Ferredoxin—NADP(+) reductase Protein Binding |
| Zdroj: | Journal of Molecular Biology. 319:1133-1142 |
| ISSN: | 0022-2836 |
| DOI: | 10.1016/s0022-2836(02)00388-1 |
| Popis: | The flavoenzyme ferredoxin-NADP+ reductase (FNR) catalyses the production of NADPH in photosynthesis. The three-dimensional structure of FNR presents two distinct domains, one for binding of the FAD prosthetic group and the other for NADP+ binding. In spite of extensive experiments and different crystallographic approaches, many aspects about how the NADP+ substrate binds to FNR and how the hydride ion is transferred from FAD to NADP+ remain unclear. The structure of an FNR:NADP+ complex from Anabaena has been determined by X-ray diffraction analysis of the cocrystallised units to 2.1 A resolution. Structural perturbation of FNR induced by complex formation produces a narrower cavity in which the 2'-phospho-AMP and pyrophosphate portions of the NADP+ are perfectly bound. In addition, the nicotinamide mononucleotide moiety is placed in a new pocket created near the FAD cofactor with the ribose being in a tight conformation. The crystal structure of this FNR:NADP+ complex obtained by cocrystallisation displays NADP+ in an unusual conformation and can be considered as an intermediate state in the process of coenzyme recognition and binding. Structural analysis and comparison with previously reported complexes allow us to postulate a mechanism which would permit efficient hydride transfer to occur. Besides, this structure gives new insights into the postulated formation of the ferredoxin:FNR:NADP+ ternary complex by prediction of new intermolecular interactions, which could only exist after FNR:NADP+ complex formation. Finally, structural comparison with the members of the broad FNR structural family also provides an explanation for the high specificity exhibited by FNR for NADP+/H versus NAD+/H. |
| Databáze: | OpenAIRE |
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