IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Kinetic and structural study of the ferredoxin-NADP reductase from Xanthomonas axonopodis pv. citri
Autor/es:
TONDO, MARÍA LAURA; MUSUMECI, MATÍAS A.; ORELLANO, ELENA G.; CECCARELLI, EDUARDO A.
Lugar:
San Miguel de Tucumán, Tucumán , Argentina
Reunión:
Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2009
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)
Resumen:
Ferredoxin-NADP(H) reductases (FNRs) are FAD-containing monomeric enzymes that deliver NADPH or low potential one-electron donors (ferredoxin, flavodoxin, adrenodoxin) to redox-based metabolisms in plastids, mitochondria and bacteria. The FNR variants present in most prokaryotes (FPRs) can be phylogenetically classified into two subclasses represented by the Azotobacter vinelandii (subclass I) and the Escherichia coli (subclass II) FPR prototypes. Xanthomonas axonopodis pv. citri (Xac) is a Gram-negative, aerobic bacteria that possess a single fpr gene with the characteristic features of subclass I bacterial reductases. We have expressed in E. coli and purified to homogeneity the recombinant Xac FPR protein, rendering a monomeric product with an absorption spectrum characteristic of flavin-containing proteins. Then, we further characterized Xac FPR protein by analyzing its kinetic behavior and interaction with the substrates NADPH, NADH, pea ferredoxin and E. coli flavodoxin. The accessibility of the prosthetic group FAD was also evaluated. Comparative analysis of the collected results with those reported for typical plastidic (i.e. pea) and bacterial (i.e. E. coli) FNRs suggest that Xac FPR resembles plastidic reductases regarding the interaction with nucleotidic substrates and the prosthetic group, but displays kinetic parameters typical of bacterial flavoenzymes.