Zinc Fingers: A Novel Protein Fold for Nucleic Acid Recognition

An essential part of gene expression and regulation is the binding of a regulatory protein to the recognition sequence of the gene on which it acts. Many such proteins have embedded in their structures a domain, or motif, that serves for binding to DNA. The best-understood protein structure used for DNA binding is the helix-turn-helix motif seen in the crystal structure of several bacterial regulatory proteins (for review, see Pabo and Sauer 1984; Anderson et al. 1987). Amino acid sequences that could form a similar structural motif are also present in the homeo box region of several eukaryotic proteins (Gehring 1985).