InterPro domain: IPR003340

Two DNA binding proteins, RAV1 and RAV2 from Arabidopsis thaliana contain two distinct amino acid sequence domains found only in higher plant species. The N-terminal regions of RAV1 and RAV2 are homologous to the AP2 DNA-binding domain (see IPR001471 ) present in a family of transcription factors, while the C-terminal region exhibits homology to the highly conserved C-terminal domain, designated B3, of VP1/ABI3 transcription factors [ 1 ]. The AP2 and B3-like domains of RAV1 bind autonomously to the CAACA and CACCTG motifs, respectively, and together achieve a high affinity and specificity of binding. It has been suggested that the AP2 and B3-like domains of RAV1 are connected by a highly flexible structure enabling the two domains to bind to the CAACA and CACCTG motifs in various spacings and orientations [ 2 ].

This entry represents the B3 DNA binding domain. Its DNA binding activity has been demonstrated [ 2 ]. The B3 domain can be found in one or more copies.

1. RAV1, a novel DNA-binding protein, binds to bipartite recognition sequence through two distinct DNA-binding domains uniquely found in higher plants. Nucleic Acids Res. 27, 470-8
2. The conserved B3 domain of VIVIPAROUS1 has a cooperative DNA binding activity. Plant Cell 9, 799-807