Research On The Structure And Function Of NPR1 Protein And Its Partner

Salicylic acid(SA)is a mandatory plant metabolite in the deployment of systemic acquired resistance(SAR),a broad-spectrum systemic immune response induced by local inoculation with avirulent pathogens.The nonexpresser of PR genes(NPR1)transcription co-activator is the central node positively regulating SAR.NPR1 is a intersection of different disease resistant pathways,also plays a key role in induced systemic immune(ISR)and linked to the circadian clock through redox rhythms regulation,NPR1 has been widely concerned as an important immune related proteins,and its homologous protein NPR3/NPR4 plays an important role in the immune process.In this research,we purified the NPR1/NPR4 protein and optimized the crystal.We cut the NPR1/NPR4 protein by restriction enzyme digestion,truncated the NPR1/NPR4 combined with mass spectrometry and N-terminal sequencing.The expression,purification and crystal optimization were carried out on the basis of the truncation,crystal of NPR1 truncation have been found ultimately.According to the literature,we used transcription factor TGA3,WRKY70 and phosphorylated kinase SnRK2.8 interact with NPR1,and used CUL3 A and its truncation to test the interaction with NPR4 and its truncation.We displayed mutation at cysteine and posttranslational modification site of NPR1 while deficiency of complex assembly.The mutation test indicate that the SUMO modification site(SIM3)of NPR1 has an effect on the three-dimensional structure of NPR1 and plays a key role in protein-protein interaction.This research carry forward the crystal structure analysis of NPR1 and expect to analyze the molecular mechanism of NPR1 in SA pathway via structure biology.