FIGURE 4.

PFA inhibition of DNA synthesis for multiple nucleotide incorporation events. Reactions were monitored in the presence of constant concentrations of dNTPs and increasing concentrations of PFA. The reactions conditions were chosen such that the maximum of the available primer-template substrate was used in the absence of PFA. PFA-mediated inhibition of DNA synthesis is illustrated by the reduction of the intensity of the signal corresponding to the migration pattern of a full-length product (fl) that is indicated by the corresponding arrow. The migration pattern of the 5′ end radioactively labeled primer (s) and the product of the terminal transferase activity (tt) is illustrated by corresponding arrows. The asterisk points to the exogenous background exonuclease activity present in samples with HCMV polymerase UL54 expressed in vitro transcription/translation system.