This is a bacterial family of proteins with unknown function. AbiGi is a family of putative type IV toxin-antitoxin system antitoxins. The AbiG abortive phage resistance system affects lactococcal bacteriophages phiP335 and phiQ30 but not the other P335 phage species. AbiGii toxin appears to confer resistance to phages by a mechanism of abortive infection that acts by interfering with phage RNA synthesis [1]. The cognate toxin is found in Pfam:PF16873.

1: Effectiveness of the lactococcal abortive infection systems AbiA, AbiE, AbiF and AbiG against P335 type phages. Tangney M, Fitzgerald GF; FEMS Microbiol Lett. 2002;210:67-72. PMID:12023079

2: AbiG, a genotypically novel abortive infection mechanism encoded by plasmid pCI750 of Lactococcus lactis subsp. cremoris UC653. O'Connor L, Coffey A, Daly C, Fitzgerald GF; Appl Environ Microbiol. 1996;62:3075-3082. PMID:8795193

3: Expression, regulation, and mode of action of the AbiG abortive infection system of lactococcus lactis subsp. cremoris UC653. O'Connor L, Tangney M, Fitzgerald GF; Appl Environ Microbiol. 1999;65:330-335. PMID:9872803