Part of the adaptive DNA-repair response to alkylating agents. Could prevent alkylation damage by protecting DNA and destroying alkylating agents that have yet to reach their DNA target. Binds to double-stranded DNA with a preference for a DNA region that includes its own promoter. Shows weak isovaleryl-CoA dehydrogenase activity in vitro. Homotetramer. Dimer of dimers. Regulated by Ada in response to alkylating agents. Also induced by anaerobiosis or by acetate at pH 6.5, via RpoS. Represses its own synthesis during normal cell growth. The N-terminal region contains FAD-dependent dehydrogenase activity and the C-terminal region contains DNA-binding activity. Belongs to the acyl-CoA dehydrogenase family. Extended N-terminus. Extended N-terminus.