Fig. 5: Structural basis of viral inhibition of DSR2 defense.
From: Molecular basis of bacterial DSR2 anti-phage defense and viral immune evasion
Top and side views of the cryo-EM density map (A) and the atomic model (B) of the DSR2-DSAD1 complex. Four DSR2s are colored in pale green, forest, light blue, and teal; DSAD1 proteins are colored in purple. C Schematic model of DSR2-DSAD1 co-complex formation resulting in inhibition of NAD+ hydrolysis by DSR2 due to absence of Tube protein. Same color code as in (A); Tube is shown in yellow. D Structural alignment of a DSAD1 (purple) and Tube (yellow) both binding to the same site on DSR2 (teal). The steric clash between DSAD1 and Tube protein occurs at the same binding interface of the DSR2 CTD. E Overall structure of the DSR2-DSAD1 complex, DSR2s are colored in blue and cyan; DSAD1 proteins are colored in orange. F−H Detailed insights into the interactions between DSR2 and DSAD1 protein. Two major regions of hydrophobic interactions and one major region of hydrogen bonding interactions between DSR2 and DSAD1. Key interacting residues are shown in stick representation. Hydrogen bonds are shown in black dashed lines. I In vitro NAD+ degradation assays of wild-type DSR2 and the DSR2-DSAD1 complex. DSR2-DSAD1 significantly reduces NAD+ cleavage activity. Data are presented as means ± SE (n = 5 independent experiments).
