Toxic component of a type I toxin-antitoxin (TA) system (PubMed:16166525). Overexpression of txpA causes cell lysis; the TxpA protein has been suggested to act on the cell membrane or might possibly block cell wall synthesis (PubMed:16166525). Overexpression in E.coli is not toxic (PubMed:16166525). The antisense RNA ratA acts as an antitoxin by annealing to the mRNA of txpA and causing its degradation, protecting the cell from TxpA by blocking the production of the toxin. A type I toxin-antitoxin (TA) system, where expression of the proteinaceous toxin is controlled by an antisense sRNA. Encoded in a 48-kb, phage-like element known as skin.