Cloning and characterization of a theta class glutathione transferase from the potato pathogen Phytophthora infestans.
A glutathione transferase (GST) related to the theta (T) class of enzymes found in plants and animals has been cloned from the potato pathogen Phytophthora infestans. The cDNA encoded a 25kDa polypeptide termed PiGSTT1 which was expressed in E. coli as the native protein. The purified recombinant enzyme behaved as a dimer (PiGSTT1-1) and while being unable to catalyse the glutathione conjugation of 1-chloro-2,4-dintrobenzene, was highly active as a glutathione peroxidase with organic hydroperoxide substrates. In addition to reducing the synthetic substrate cumene hydroperoxide, PiGSTT1-1 was shown to be highly active toward 9(S)-hydroperoxy-(10E,12Z,15Z)-octadecatrienoic acid=9(S)-HPOT, which is formed in potato plants during infection by P. infestans as a precursor of the antifungal oxylipin colnelenic acid. An antiserum was raised to PiGSTT1-1 and used to demonstrate that the respective enzyme was abundantly expressed in P. infestans both cultured on pea agar and during the infection of potato plants.
Bryant
David
D
School of Biological and Biomedical Sciences, Crop Protection Group, Durham University, South Road, Durham DH1 3LE, UK.
Cummins
Ian
I
Dixon
David P
DP
Edwards
Robert
R
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D015870:Gene Expression; D005982:Glutathione Transferase / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D019787:Linoleic Acid / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010838:Phytophthora / Q000201:enzymology* / Q000235:genetics*; D010935:Plant Diseases; D016415:Sequence Alignment; D011198:Solanum tuberosum / Q000382:microbiology*
D019787:Linoleic Acid; D005982:Glutathione Transferase