Cloning and characterization of the ferredoxin-NADP reductase from Xanthomonas axonopodis pv. citri

TONDO, M.L.; DELPRATO; M.L.; OTTADO, J.; ORELLANO, E.G.

Rosario

Congreso; XLII Reunión Anual de SAIB (Sociedad Argentina de Investigación en Bioquímica y Biología Molecular); 2006

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Xanthomonas axonopodis pv. citri (Xac) is the phytopathogen responsible for citrus canker. In plant-microbe interactions, increased production of reactive oxygen species (ROS) is an important component of the active plant defense response, which is thought to function directly in growth inhibition of pathogens. In order to survive and proliferate, bacteria evolve enzymatic and non-enzymatic mechanisms to rapidly detoxify ROS. One of the enzymes involved in the oxidative stress response in bacteria is ferredoxin-NADP(H) reductase (Fpr/FNR), which mediate reversible redox reactions between NADP(H) and one-electron carriers, such as ferredoxin or flavodoxin. The Fpr activity is thought to keep NADPH at tolerable levels during the progress of the stress condition. Recently, the genome of Xac has been sequenced and the fpr gene identified. The sequence analysis of the Fpr protein revealed characteristic features of the subclass I of bacterial FNRs, represented by the Azotobacter vinelandii prototype. We present the molecular cloning of the fpr gene from the bacterial genome and an efficient expression and purification system of the recombinant protein. We determined the spectral properties and kinetic parameters of Xac Fpr and found that they are very similar to those reported for other type I bacterial FNRs.