Viral proteins activate PARIS-mediated tRNA degradation and viral tRNAs rescue infection.

ABSTRACT: Viruses compete with each other for limited cellular resources, and some viruses deliver defense mechanisms that protect the host from competing genetic parasites. PARIS is a defense system, often encoded in viral genomes, that is composed of a 53 kDa ABC ATPase (AriA) and a 35 kDa TOPRIM nuclease (AriB). Here we show that AriA and AriB assemble into a 425 kDa supramolecular immune complex. We use cryo-EM to determine the structure of this complex which explains how six molecules of AriA assemble into a propeller-shaped scaffold that coordinates three subunits of AriB. ATP-dependent detection of foreign proteins triggers the release of AriB, which assembles into a homodimeric nuclease that blocks infection by cleaving the host tRNA^Lys. Phage T5 subverts PARIS immunity through ex

SUBMITTER: Burman N 

PROVIDER: S-EPMC10802454 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature