Figure 1.

Strategy for affinity cleavage of DNA by TBP K97C-OP and E188C-OP. (A) K97C and E188C yTBP. These two variants were chosen because they allow a DNA cleavage agent to be placed on equivalent positions of the N- and C-terminal stirrups, respectively, with a minimum of steric interference. (B) Experimental strategy. Scheme illustrating the regions of the promoter that are expected to be cleaved in the specified orientation. N and C refer to the pseudosymmetrical halves of TBP_c formed by the N- and C-terminal repeats, respectively. All crystal structures of eukaryotic TBP_c-containing promoter complexes show the N-terminal domain of TBP_c facing downstream toward the start site of transcription. The lengths of the flanking DNA are not drawn to scale.