FIG. 3.

Increasing E1 concentration is not sufficient to overcome inhibition by TBPc in cell-free replication assays. (A) NdeI-digested replication products from cell-free replication assays using HPV-11 ori-containing plasmid (pUC18/7870-99) and increasing E1. Cell-free replication assays were performed as outlined in Materials and Methods. E1, E2, and TBPc are added as noted. Lanes correlating to initial intensity (I₀) are indicated. (B) Several replication assays with (circles) and without (squares) TBPc were quantified by PhosphoImager and filter washing as outlined in Materials and Methods. The data were fit to single rectangular hyperbolic curves (r² = 0.97 and 0.95, with and without TBPc present, respectively). Note that the curves generated by the data indicate that TBPc acts as a noncompetitive inhibitor.