مطالعه بیوانفورماتیکی تنوع آمینواسیدی پروتئین Rcr3 در خانواده سولاناسه و تاثیر آن در برهمکنش با افکتورAvr2 قارچ Cladosporium fulvum

Pathogens secrete small proteins so-called effector for successful colonization and to overcome host defense system. Fungus Cladosporium fulvum is a biotroph pathogen of tomato (solanum lycopersicum) that secrete numerous effectors into the apoplast. One of these effectors known as Avr2 that inhibits the protease activity of pathogenesis-related protein Rcr3 of tomato leading to compatible interaction. However, in incompatible interactions, the complex of Avr2 and Rcr3 can be sensed by immune receptor Cf2 of tomato leading to activation of host defense. Biological assays have shown that Rcr3 of other solanaceous plants can also be recognized when expressed in Nicotiana benthamiana leaves in the presence of Avr2 and Cf2. For this study, we used the amino acid sequence of Rcr3 (inducing- and non-inducing-hypersensitive response (HR)) from ten solanaceous plants. Using PDB data we obtained the best model with the highest score for both Avr2 and Rcr3. The best model of Avr2 to the resolved crystal structures was used for docking in Cluspro. We assessed the polymorphism of Rcr3 sequences from various solanaceous plants and evaluated its impact on the 3D structure of Rcr3 protein at the interface (active site) with Avr2 in both inducible and non-inducible groups. Data revealed that various amino acid substitutions occur at the active site of Rcr3. Despite the polymorphism of Rcr3 sequence, the 3D structure of its active site is conserved in incompatible group, which is required for the induction of a hypersensitive response. In the compatible group, these substitutions were drastically changed the active site structure of Rcr3, possibly corrupting the complex of Avr-Rcr3-Cf2.