Characterization of additional peaks of necrosis activity from Pyrenophoratritici-repentis

Ptr ToxA is coded by a single gene but two to three peaks of necrosis toxin activity were identified during the final purification step from several P yrenophora tritici-repentis isolates. All three peaks cross reacted with an tibodies raised against the purified necrosis toxin. One peak of activity i s proposed to be a folding intermediate of the toxin based on circular dich roism spectroscopy and mass spectrometry. The kinetics and pH dependecne of the folding process were investigated.