Molecular basis for anti-jumbo phage immunity by AVAST type 5

 Highlights

• Avs5 is activated at the early phage infection vesicle

• Avs5 hydrolyzes NAD+ to block jumbo phage nucleus formation

• Divergent Avs5 clades sense JADA to inhibit jumbo phage infection

• JADA is an essential early phage protein with a novel protein fold

Summary

Jumbo phages protect their genomes from DNA-sensing bacterial defense systems by enclosing them within vesicles and nucleus-like compartments. Very little is known about defense systems specialized to counter these phages. Here, we show that AVAST type 5 (Avs5) systems, part of the signal transduction ATPases of numerous domains (STAND) superfamily, confer conserved immunity against jumbo phages. Using fluorescence microscopy and biotin proximity labeling, we demonstrate that Avs5 localizes to early infection vesicles, where it senses an essential, early-expressed phage protein named JADA (Jumbo phage Avs5 Defense Activator). Recognition of phage infection triggers the Sir2-like effector domain of Avs5 across three Avs5 clades, resulting in rapid NAD+ hydrolysis, disruption of phage nucleus formation, and arrest of infection. These findings reveal a spatially coordinated bacterial immune strategy that targets an early vulnerability in jumbo phage infection.

Read full article at:

https://www.sciencedirect.com/science/article/pii/S1097276526000249#