Tandem DNA binding proteins: 9-cis retinoic acid receptor (magenta) and The thyroid hormone receptor has an additonal alpha-helix shown. They bind to the tandem sequence (defined on the same strand) of AGGTCA. Highlighted are the G (purple), T (yellow), C (green), and A (blue). Each DNA-binding protein uses an alpha-helix to fit into the major groove, and is held together by zinc atoms. They use a motif different from a "zinc finger". Structural determinants of nuclear receptor assembly on DNA direct repeats. Rastinejad F, Perlmann T, Evans RM, Sigler PB. Nature. 1995 May 18;375(6528):203-11. (PubMed) 2NLL (PDB) |