Sequence specific block of in vitro DNA synthesis with isopropyl phosphotriesters in template oligodeoxyribonucleotides.

We have synthesized four oligodeoxyribonucleotides each bearing an isopropyl phosphotriester at a defined position. These oligomers were used as templates for in vitro DNA synthesis catalyzed by Escherichia coli DNA polymerase I large fragment. Results showed that the phosphotriester inhibits the DNA chain elongation and the level of the inhibition is dependent on the base 5' to the phosphotriester.