Fig 1. Structural stability, overview of individual CARDs and the key residues that drive CARD-CARD interaction.

(A) Graphs depict the backbone RMSD and Rg of individual CARDs. (B) Secondary structure components of both NOD1 and RIP2 CARDs during the course of simulation time (the colour segments provided just below the figure represents the secondary structure properties). (C) Cartoon representations of NOD1^CARD and (D) RIP2^CARD displayed the six-helix structural folds (left panel) and electrostatic surface potentials (right panel). The key residues (that were reported or, predicted (in this study) to be involved in CARD-CARD interaction; were presented in sphere-stick model in different colours. The predicted residues are presented in grey and reported residues were portrayed according to their physicochemical properties. The surface view of CARD models shows distinct positive (blue) and negative (red) surface patches. The dotted lines represent the type-I surface patches (blue: type-Ia and red: type-Ib). (E) Multiple sequence alignment of NOD1 and RIP2 CARDs from human (HU), cattle (CA), mouse (MO) and zebrafish (ZF) indicates the key interacting residues. The reported key interacting residues are coloured based on their physicochemical properties.