Effect of aphidicolin and nucleotide analogs on the phage phi 29 DNA polymerase

The drugs aphidicolin and the nucleotide analogs butylanilino dATP, butylphenyl dGTP, and butylphenyl rGTP inhibited the protein-primed replication of phi 29 DNA-protein p3 in the presence of purified terminal protein p3 and phi 29 DNA polymerase p2. The effect of aphidicolin was mainly on the polymerization reaction by decreasing the rate of elongation. The nucleotide analogs inhibited both the formation of the p3-dAMP initiation complex and its further elongation, the latter being also due to a decrease in the elongation rate. When assayed with the phi 29 DNA polymerase as the only protein, all the drugs inhibited polymerization on activated DNA as well as the 3'----5' exonuclease activity of the polymerase, indicating that the target of the drugs is the phi 29 DNA polymerase itself.