Analogous to an antitoxin, this small protein potentially acts as a negative regulatory component that might sense the presence of invaders by acting as a binding factor or substrate for invader-encoded enzymes like viral peptidases in certain CxC ABC ATPase-based DNA modification systems [1].

1: Comprehensive classification of ABC ATPases and their functional radiation in nucleoprotein dynamics and biological conflict systems. Krishnan A, Burroughs AM, Iyer LM, Aravind L; Nucleic Acids Res. 2020;48:10045-10075. PMID:32894288