Solution structure of the core NFATC1/DNA complex.

The nuclear factor of the activated T cell (NFAT) family of transcription factors regulates cytokine gene expression by binding to the promoter/enhancer regions of antigen-responsive genes, usually in cooperation with heterologous DNA-binding partners. Here we report the solution structure of the binary complex formed between the core DNA-binding domain of human NFATC1 and the ARRE2 DNA site from the interleukin-2 promoter. The structure reveals that DNA binding induces the folding of key structural elements that are required for both sequence-specific recognition and the establishment of cooperative protein-protein contacts. The orientation of the NFAT DNA-binding domain observed in the binary NFATC1-DBD*/ DNA complex is distinct from that seen in the ternary NFATC2/AP-1/DNA complex, suggesting that the domain reorients upon formation of a cooperative transcriptional complex.