The DNA-binding domains of TetR recognize a 15 base pair palindromic sequence  of the TetA operator. These domains mainly consist of a helix-turn-helix (HTH) motif that is common in TetR protein family members (see below). However, the N-terminal residues preceding this motif have also been shown to be important for DNA binding.
The recognition of specific DNA sequences by TetR is crucial for its function. The protein's ability to bind to a 15 base pair palindromic sequence within the TetA operator is essential for its regulatory activity, and this is achieved through a combination of an HTH motif and N-terminal residues.