B3 domain

B3 domain

B3 DNA binding domain
B3 DNA binding domain of RAV1
Symbol B3_domain
Pfam PF02362
InterPro IPR003340
SCOP 1wid
CDD cd10017

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.[1]

B3 families

In Arabidopsis thaliana, there are three main families of transcription factors that contain B3 domain:[2]

  • 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[1] molecular model[1] NMR[1]
B3 recognition sequence TGTCTC[3][4] CATGCA[5][6] CACCTG[7]

[1] and ​[8] 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.[9][10]

See also


  1. ^ a b c d e
  2. ^
  3. ^
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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