167999 20260127151102.0 sideral 61052 ART-2009-61052 eng Bortolotti, Ana Coenzyme binding and hydride transfer in Rhodobacter capsulatus ferredoxin/flavodoxin NADP(H) oxidoreductase. 2009 Access copy available to the general public Unrestricted Ferredoxin-NADP(H) reductases catalyse the reversible hydride/electron exchange between NADP(H) and ferredoxin/flavodoxin, comprising a structurally defined family of flavoenzymes with two distinct subclasses. Those present in Gram-negative bacteria (FPRs) display turnover numbers of 1–5 s−1 while the homologues of cyanobacteria and plants (FNRs) developed a 100-fold activity increase. We investigated nucleotide interactions and hydride transfer in Rhodobacter capsulatus FPR comparing them to those reported for FNRs. NADP(H) binding proceeds as in FNRs with stacking of the nicotinamide on the flavin, which resulted in formation of charge-transfer complexes prior to hydride exchange. The affinity of FPR for both NADP(H) and 2′-P-AMP was 100-fold lower than that of FNRs. The crystal structure of FPR in complex with 2′-P-AMP and NADP+ allowed modelling of the adenosine ring system bound to the protein, whereas the nicotinamide portion was either not visible or protruding toward solvent in different obtained crystals. Stabilising contacts with the active site residues are different in the two reductase classes. We conclude that evolution to higher activities in FNRs was partially favoured by modification of NADP(H) binding in the initial complexes through changes in the active site residues involved in stabilisation of the adenosine portion of the nucleotide and in the mobile C-terminus of FPR. info:eu-repo/semantics/openAccess by https://creativecommons.org/licenses/by/4.0/deed.es 2.48 2009 BIOPHYSICS 41 / 74 = 0.554 2009 Q3 T2 BIOCHEMISTRY & MOLECULAR BIOLOGY 153 / 281 = 0.544 2009 Q3 T2 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Pérez-Dorado, Inmaculada Goñi, Guillermina (orcid)0000-0003-4010-849X Medina, Milagros Universidad de Zaragoza (orcid)0000-0001-8743-0182 Hermoso, Juan A. Carrillo, Néstor Cortez, Néstor 1002 060 Universidad de Zaragoza Dpto. Bioq.Biolog.Mol. Celular Área Bioquímica y Biolog.Mole. 1794, 2 (2009), 199-210 BBA-Proteins Proteomics Biochimica et Biophysica Acta - Proteins and Proteomics 1570-9639 231676 http://zaguan.unizar.es/record/167999/files/texto_completo.pdf Postprint 1147232 http://zaguan.unizar.es/record/167999/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:167999 articulos driver 2026-01-27-15:07:29 ARTICLE