TALE repeats recognize individual bases in DNA. Each TALE repeat contains 34 amino acids, two of which specify its nucleotide binding partner. In this figure, the identity of these residues is indicated by the color of the repeat. TALE proteins can be designed to uniquely recognize extended oligonucleotide sequences. In this example, a 22 base-pair sequence is bound by a single TALE protein, the bacterial effector PthXo1.

[Drawn from 3UGM.pdb]