Artículo
A hydrogen bond network in the active site of Anabaena ferredoxin-NADP + reductase modulates its catalytic efficiency
Autor/es | Sánchez Azqueta, Ana
Herguedas, Beatriz Hurtado Guerrero, R. Hervás Morón, Manuel Navarro Carruesco, José Antonio Martínez Júlvez, Marta Medina, Milagros |
Fecha de publicación | 2014 |
Fecha de depósito | 2018-02-06 |
Publicado en |
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Resumen | Ferredoxin-nicotinamide-adenine dinucleotide phosphate (NADP+) reductase (FNR) catalyses the production of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) in photosynthetic organisms, where its flavin adenine ... Ferredoxin-nicotinamide-adenine dinucleotide phosphate (NADP+) reductase (FNR) catalyses the production of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) in photosynthetic organisms, where its flavin adenine dinucleotide (FAD) cofactor takes two electrons from two reduced ferredoxin (Fd) molecules in two sequential steps, and transfers them to NADP+ in a single hydride transfer (HT) step. Despite the good knowledge of this catalytic machinery, additional roles can still be envisaged for already reported key residues, and new features are added to residues not previously identified as having a particular role in the mechanism. Here, we analyse for the first time the role of Ser59 in Anabaena FNR, a residue suggested by recent theoretical simulations as putatively involved in competent binding of the coenzyme in the active site by cooperating with Ser80. We show that Ser59 indirectly modulates the geometry of the active site, the interaction with substrates and the electronic properties of the isoalloxazine ring, and in consequence the electron transfer (ET) and HT processes. Additionally, we revise the role of Tyr79 and Ser80, previously investigated in homologous enzymes from plants. Our results probe that the active site of FNR is tuned by a H-bond network that involves the side-chains of these residues and that results to critical optimal substrate binding, exchange of electrons and, particularly, competent disposition of the C4n (hydride acceptor/donor) of the nicotinamide moiety of the coenzyme during the reversible HT event. |
Identificador del proyecto | BIO2010-14983
B18 BIO-022 |
Cita | Sánchez Azqueta, A., Herguedas, B., Hurtado Guerrero, R., Hervás Morón, M., Navarro Carruesco, J.A., Martínez Júlvez, M. y Medina, M. (2014). A hydrogen bond network in the active site of Anabaena ferredoxin-NADP + reductase modulates its catalytic efficiency. Biochimica et Biophysica Acta - Bioenergetics, 1837, 251-263. |
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A hydrogen bond network.pdf | 1.819Mb | [PDF] | Ver/ | |