tRNA nuclease CdiA

UniProtKB accession:  P0DSI1

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UniProtKB description:  Toxic component of a toxin-immunity protein module, which functions as a cellular contact-dependent growth inhibition (CDI) system. CDI modules allow bacteria to communicate with and inhibit the growth of closely related neighboring bacteria in a contact-dependent fashion (target cell counts decrease about 10,0000-fold for this system). CdiA toxicity is neutralized by its cognate immunity protein CdiI-NC101, but not by CdiI from other bacteria (PubMed:26305955, PubMed:28973472). The C-terminal domain (CT) cleaves tRNA endonucleolytically at the 5' side of guanine discriminator nucleotide sites (removes the last 4 nucleotides of the tRNA acceptor arm when the first nucleotide to be removed is G) (PubMed:28973472). Requires EF-Ts (tsf) for toxic function of the CT domain in vivo (PubMed:28223500). In vitro the CT tRNase activity requires both EF-Tu (tufA) and EF-Ts. EF-Ts probably increases steady-state GTP-EF-Tu-aa-tRNA substrate levels. The CT domain is thought to remodel this same complex to displace the 3'-end of the aa-tRNA and allow it to enter into the toxin active site (PubMed:28973472). The CT domain gains access to the cytoplasm of target cells by using integral inner membrane protein PTS system glucose-specific EIICB component (ptsG) (PubMed:26305955).