Toxic component of a type I toxin-antitoxin (TA) system. Inhibits ATP synthesis possibly due to its insertion in the cell inner membrane, ATP levels drop over 50% 2 minutes after induction (PubMed:24513967). Overexpression is toxic leading to cell death, it inhibits cell growth within 30 minutes; C-terminally tagged versions of the protein are toxic while N-terminally tagged versions are not (PubMed:24513967). Expression of the proteinaceous toxin is probably controlled by an antisense sRNA, in this case RdlA. Only a few of these TA systems have been mechanistically characterized; the mechanisms used to control expression of the toxin gene are not necessarily the same (Probable). Belongs to the Ldr toxic peptide family.