B3 domain
The B3 DNA binding domain (DBD) is a highly conserved domain found exclusively in transcription factors (≥40 species) (Pfam PF02362) combined with other domains (InterPro: IPR003340). It consists of 100-120 residues, includes seven beta strands and two alpha helices that form a DNA-binding pseudobarrel protein fold (SCOP 117343); it interacts with the major groove of DNA. == B3 families == In Arabidopsis thaliana, there are three main families of transcription factors that contain B3 domain: ARF (Auxin Response Factors) ABI3 (ABscisic acid Insensitive3) RAV (Related to ABI3/VP1) PDB: 1WID and PDB: 1YEL are only known NMR solution phase structures of the B3 DNA Binding Domain.