DNA-binding protein that negatively regulates its own transcription (PubMed:10973967, PubMed:11809882). Interferes with RNA polymerase (RNAP) recruitment by inhibiting the association of RNAP with the TBP-TFB promoter complex (PubMed:11809882). Binds to a 46-base pair sequence that overlaps the transcriptional start site of its own promoter (PubMed:10973967). Homooctamer; tetramer of dimers (PubMed:10973967, PubMed:11230123, PubMed:11375518). Forms a homodimer mainly through interactions between the antiparallel beta-sheets of the C-terminal domain, and further interactions lead to octamer formation (PubMed:11230123). Consists of an N-terminal domain containing a helix-turn-helix (HtH) DNA-binding motif, and a C-terminal domain of mixed alpha/beta character reminiscent of a number of RNA- and DNA-binding domains.