InterPro domain: IPR003657

The WRKY domain is a 60 amino acid region that is defined by the conserved amino acid sequence WRKYGQK at its N-terminal end, together with a novel zinc-finger-like motif. The WRKY domain is found in one or two copies in a superfamily of plant transcription factors involved in the regulation of various physiological programs that are unique to plants, including pathogen defence, senescence, trichome development and the biosynthesis of secondary metabolites. The WRKY domain binds specifically to the DNA sequence motif (T)(T)TGAC(C/T), which is known as the W box. The invariant TGAC core of the W box is essential for function and WRKY binding [ 1 ]. Some proteins known to contain a WRKY domain include Arabidopsis thaliana ZAP1 (Zinc-dependent Activator Protein-1) and AtWRKY44/TTG2, a protein involved in trichome development and anthocyanin pigmentation; and wild oat ABF1-2, two proteins involved in the gibberelic acid-induced expression of the alpha-Amy2 gene.

Structural studies indicate that this domain is a four-stranded beta-sheet with a zinc binding pocket, forming a novel zinc and DNA binding structure [ 2 ]. The WRKYGQK residues correspond to the most N-terminal beta-strand, which enables extensive hydrophobic interactions, contributing to the structural stability of the beta-sheet.

1. The WRKY superfamily of plant transcription factors. Trends Plant Sci. 5, 199-206
2. Solution structure of an Arabidopsis WRKY DNA binding domain. Plant Cell 17, 944-56