B3 domain

B3 DNA binding domain
B3 DNA binding domain of RAV1
Identifiers
Symbol	B3_domain
Pfam	PF02362
InterPro	IPR003340
PROSITE	PS50863
SCOP	1wid
SUPERFAMILY	1wid
CDD	cd10017
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The B3 DNA binding domain (DBD) is a highly conserved domain found exclusively in transcription factors, from higher plants (≥40 species) (Pfam PF02362) combined with other domains (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)

protein	ARF1-B3	ABI3-B3	RAV1-B3
B3 structure derived by	molecular model	molecular model	NMR
B3 recognition sequence	TGTCTC	CATGCA	CACCTG

PDB: 1WID​ and PDB: 1YEL​ are only known NMR solution phase structures of the B3 DNA Binding Domain.

Related proteins

The N-terminal domain of restriction endonuclease EcoRII; the C-terminal domain of restriction endonuclease BfiI possess a similar DNA-binding pseudobarrel protein fold.

See also

• Restriction endonuclease EcoRII
• Auxin
• Abscisic acid

External links

• DBD database of predicted transcription factors Uses a curated set of DNA-binding domains to predict transcription factors in all completely sequenced genomes
• Classification in the "Transcription factors" table according to the Transfac database.
• Database of Arabidopsis Transcription Factors
• B3, RAV, and ARF family at PlantTFDB:Plant Transcription Factor Database