NADPH-dependent glutathione peroxidase-like proteins (Gpx-1, Gpx-2) reduce unsaturated fatty acid hydroperoxides in Synechocystis PCC 6803

Here ne isolated and characterized two genes (slr1171, slr1992) designated gpx-1 and gpx-2, respectively, encoding glutathione peroxidase (GPX)-like proteins (Gps-1, Gpx-2) from Synechystis PCC 6803. The deduced amino acid sequences for gpx-1 and gpx-22 showed high similarity to those of GPX-like proteins from higher plants and mammalian GPXs, respectively. Surprisingly, both recombinant proteins in Escherichia coli H ere able to utilize NADPH, but not reduced glutathione, as an electron donor and unsaturated fatty acid hydroperosides or alkyl hydroperosides as an acceptor. It seems accurate to refer to Gpx-1 and Gpx-2 as NADPH-dependcnt GPX-like proteins that serve as a new defense system for the reduction of unsaturated fatty acid hydroperosides. (C) 2001 Federation of European Biochemical Societies, Published bgl Elsevier Science B.V. All rights reserved.