Figure 1.

Composition of the randomized zinc finger protein libraries 1–60. A schematic representation of zinc finger 2 is shown highlighting the positions of randomization. The identities of amino acid residues, encoded within each library, in the positions −1, 3 and 6 of the α-helix of zinc finger 2 are indicated, where ‘MAX’ denotes a mixture of all 20 amino acids (comprising one codon optimal for the expression of each amino acid in E.coli). Zinc finger gene libraries were constructed by ‘MAX’ randomization (32) of the ZFH gene as described in Materials and Methods.