This is family of bacterial proteins likely to be necessary for binding to DNA and recognising the modification sites. Members are found in bacteria, archaea and on viral plasmids, and are typically between 354 and 474 amino acids in length. There is a conserved DGQHR sequence motif.

1: DNA modification by sulfur: analysis of the sequence recognition specificity surrounding the modification sites. Liang J, Wang Z, He X, Li J, Zhou X, Deng Z; Nucleic Acids Res. 2007;35:2944-2954. PMID:17439960