Chrysomelina beetlesstore 3-nitropropionic acid in form of a pretoxin,isoxazolin-5-one glucoside-conjugated ester,to protect themselves against predators.Here we identified a cytochrome P450 monooxygenase,CYP347W1,to ...Chrysomelina beetlesstore 3-nitropropionic acid in form of a pretoxin,isoxazolin-5-one glucoside-conjugated ester,to protect themselves against predators.Here we identified a cytochrome P450 monooxygenase,CYP347W1,to be involved in the production of the 3-nitropropionic acid moiety of the isoxazolin-5-one glucoside ester.Knocking down CYP347W1 led to a significant depletion in the concentration of the isoxazolin-5-one glucoside ester and an increase in the concentration of the isoxazolin-5-one glucoside in the larval hemolymph.Enzyme assays with the heterologously expressed CYP347W1 showed freeβ-alanine was not the direct substrate.Homology modeling indicated thatβ-alanine-CoA ester can fit into CYP347W1’s active site.Furthermore,we proved that Phaedon cochleariae eggs are not able to de novo synthesize 3-NPA,although both isoxazolin-5-one glucoside and its 3-NPA-conjugated ester are present in the eggs.These results provide direct evidence for the involvement of CYP347W1 in the biosynthesis of a P.cochleariae chemical defense compound.展开更多
基金supported by the Max Planck Society and the China Scholarship Council(grant number 201406300098).
文摘Chrysomelina beetlesstore 3-nitropropionic acid in form of a pretoxin,isoxazolin-5-one glucoside-conjugated ester,to protect themselves against predators.Here we identified a cytochrome P450 monooxygenase,CYP347W1,to be involved in the production of the 3-nitropropionic acid moiety of the isoxazolin-5-one glucoside ester.Knocking down CYP347W1 led to a significant depletion in the concentration of the isoxazolin-5-one glucoside ester and an increase in the concentration of the isoxazolin-5-one glucoside in the larval hemolymph.Enzyme assays with the heterologously expressed CYP347W1 showed freeβ-alanine was not the direct substrate.Homology modeling indicated thatβ-alanine-CoA ester can fit into CYP347W1’s active site.Furthermore,we proved that Phaedon cochleariae eggs are not able to de novo synthesize 3-NPA,although both isoxazolin-5-one glucoside and its 3-NPA-conjugated ester are present in the eggs.These results provide direct evidence for the involvement of CYP347W1 in the biosynthesis of a P.cochleariae chemical defense compound.
