This is the DNA binding domain of the LexA SOS regulon
repressor which prevents expression of DNA repair proteins in bacteria.
The aligned region contains a variant form of the helix-turn-helix DNA
binding motif [1].
This domain usually at the N terminus is found associated with IPR006198 the auto-proteolytic domain of LexA EC:3.4.21.88.
Luo Y, Pfuetzner RA, Mosimann S, Paetzel M, Frey EA, Cherney M, Kim B, Little JW, Strynadka NC.
Crystal structure of LexA: a conformational switch for regulation of self-cleavage.
Cell 106 2001 585-94
[PubMed: 11551506] http://dx.doi.org/10.1016/S0092-8674(01)00479-2