This family, found in various bacterial species, contains sequences that are similar to the Abi group of proteins, which are involved in bacteriophage resistance mediated by abortive infection in Lactococcus species [1,2]. The proteins are thought to have helix-turn-helix motifs, found in many DNA-binding proteins, allowing them to perform their function [3].

1: Cloning and DNA sequence analysis of two abortive infection phage resistance determinants from the lactococcal plasmid pNP40. Garvey P, Fitzgerald GF, Hill C; Appl Environ Microbiol 1995;61:4321-4328. PMID:8534099

2: Characterization of the lactococcal abiD1 gene coding for phage abortive infection. Anba J, Bidnenko E, Hillier A, Ehrlich D, Chopin MC; J Bacteriol 1995;177:3818-3823. PMID:7601848

3: Phage operon involved in sensitivity to the Lactococcus lactis abortive infection mechanism AbiD1. Bidnenko E, Ehrlich D, Chopin MC; J Bacteriol 1995;177:3824-3829. PMID:7601849