RelE-like toxin of type II toxin-antitoxin system HigB
This family carries several different examples of type II bacterial toxins of toxin-antitoxin systems including many HigB-like ones. The fold is referred to as the RelE/YoeB/Txe/Yeeu fold suggesting all examples of these are present in this family. Several plasmids with proteic killer gene-systems have been reported. All of them encode a stable toxin and an unstable antidote. Upon loss of the plasmid, the less stable inhibitor is inactivated more rapidly than the toxin, allowing the toxin to be activated. The activation of these systems results in cell filamentation and cessation of viable cell production. It has been verified that both the stable killer and the unstable inhibitor of the systems are short polypeptides. This family corresponds to the toxin.