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. The C-terminal domain (CT) endolytically cleaves tRNA(CUG-Gln) (PubMed:25174572, PubMed:28223500). Cleaves tRNA(CUG-Gln) in the acceptor stem between C70 and A71. Also cleaves tRNA(GUU-Asn). Requires wild-type EF-Tu (tufA) and GTP for activity in vivo and in vitro; EF-Ts (tsf) stimulates the tRNase but is not absolutely required in vitro (PubMed:28223500). The CdiA protein is thought to be exported from the cell through the central lumen of CdiB, the other half of its two-partner system (TPS). The TPS domain probably remains associated with CdiB while the FHA-1 domain forms an extended filament with the receptor-binding domain (RBD) at its extremity; in the secretion arrested state the C-terminus of the RBD and YP domains form a hairpin-like structure as the FHA-2, PT and CT domains are periplasmic. The YP domain is probably responsible for this arrest at the point where it re-enters the host cell periplasm. Upon binding to a target cell outer membrane receptor a signal is transmitted to activate secretion. The filament elongates slightly, the rest of CdiA is secreted and the FHA-2 domain becomes stably associated with the target cell's outer membrane where it facilitates entry of the toxic CT domain into the target cell periplasm. From there the toxic CT domain is cleaved and gains access to the target cell cytoplasm via an inner membrane protein. Probably interacts with cognate immunity protein CdiI1 (Probable). Forms a contact-dependent growth inhibition complex of EF-Tu, CdiA-CT-EC869 and CdiI-EC869 as well as a GTP, EF-Tu, CdiA-CT-EC869 complex; EF-Ts does not stably associate with either complex (PubMed:28223500). Secreted to the cell surface by CdiB, its two partner secretion pathway (TPS) partner (Probable). Toxin translocation into the target cell depends on the proton motive force (pmf) of the target cell, but not on tolA or tonB. The pmf is probably required for translocation across the target cell inner membrane from its periplasm. In the N-terminal section; belongs to the CdiA toxin family.