A transcriptional repressor, which is at a concentration in the bacterial cell of 10 nM, binds to
its target DNA sequence with a KD of 0.1 nM in the absence of its ligand, and with a KD of 1 μM in
the presence of its ligand. It also binds to non-target DNA sequences with a KD of 10 μM
regardless of the presence or absence of its ligand. The transcriptional repressor’s target DNA
sequence occurs once in the genome and there are 20,000 non-target DNA sites in the genome.
What is the specificity of the transcriptional repressor for its target site over non-target sites in
the absence of its ligand?





What is the specificity of the transcriptional repressor for its target site over non-target sites in
the presence of its ligand?