Solution Structure of an Arabidopsis WRKY DNA Binding Domain

• Published in: The Plant cell Vol. 17; no. 3; pp. 944 - 956
• Main Authors: Yamasaki, Kazuhiko, Kigawa, Takanori, Inoue, Makoto, Tateno, Masaru, Yamasaki, Tomoko, Yabuki, Takashi, Aoki, Masaaki, Seki, Eiko, Matsuda, Takayoshi, Tomo, Yasuko, Hayami, Nobuhiro, Terada, Takaho, Shirouzu, Mikako, Tanaka, Akiko, Seki, Motoaki, Shinozaki, Kazuo, Yokoyama, Shigeyuki
• Format: Journal Article
• Language: English
• Published: England American Society of Plant Biologists 01.03.2005
• Subjects: Amino Acid Sequence; amino acid sequences; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Atoms; Base Sequence; Binding Sites; Chemical equilibrium; DNA; DNA, Plant - genetics; DNA, Plant - metabolism; DNA-binding domains; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Genes; Hydrogen bonds; Models, Molecular; Molecular Sequence Data; Nuclear Magnetic Resonance, Biomolecular; Plant cells; protein secondary structure; Protein Structure, Secondary; Protein Structure, Tertiary; Proteins; Sequence Homology, Amino Acid; Solutions; Static Electricity; Titration; Transcription factors; Transcription Factors - chemistry; Transcription Factors - genetics; Transcription Factors - metabolism; Zinc
• ISSN: 1040-4651; 1532-298X; 1532-298X
• DOI: 10.1105/tpc.104.026435

The WRKY proteins comprise a major family of transcription factors that are essential in pathogen and salicylic acid responses of higher plants as well as a variety of plant-specific reactions. They share a DNA binding domain, designated as the WRKY domain, which contains an invariant WRKYGQK sequence and a CX₄₋₅CX₂₂₋₂₃HXH zinc binding motif. Herein, we report the NMR solution structure of the C-terminal WRKY domain of the Arabidopsis thaliana WRKY4 protein. The structure consists of a four-stranded {szligbeta}-sheet, with a zinc binding pocket formed by the conserved Cys/His residues located at one end of the {szligbeta}-sheet, revealing a novel zinc and DNA binding structure. The WRKYGQK residues correspond to the most N-terminal {szligbeta}-strand, kinked in the middle of the sequence by the Gly residue, which enables extensive hydrophobic interactions involving the Trp residue and contributes to the structural stability of the {szligbeta}-sheet. Based on a profile of NMR chemical shift perturbations, we propose that the same strand enters the DNA groove and forms contacts with the DNA bases.