[Analogs of deoxyribonucleoside-5'-triphosphates modified in the base and sugar moieties: substrate properties in DNA...

Incorporation of 2'-deoxyribonucleotide 5'-triphosphate derivatives, chemically modified both in the base and at 3'-position, into DNA by four different DNA polymerases was investigated. It is shown that 3'-azido- and 3'-amino-2',3'-dideoxy-(E)-5-(2-bromovinyl)-uridine 5'-triphosphates effectively terminate DNA synthesis catalyzed by E. coli DNA polymerase I, rat liver DNA polymerase beta, and AMV reverse transcriptase. Calf thymus DNA polymerase alpha incorporates only the 3'-amino derivative. DNA polymerases I and beta catalyse DNA synthesis in the presence of beta-D-(2'-deoxyribofuranosyl)-1-benzimidazol 5'-triphosphate, inserting the corresponding monophosphate in place of -dGTP, whereas 3'-substituted analogues of this compound were inactive in the reactions.