SYNTHESIS OF 3'-MERCAPTO-2',3'-DIDEOXYNUCLEOTIDES AND THEIR PROPERTIES IN THE DNA-SYNTHESIS BY RNA-DEPENDENT DNA-POLYMERASES

3'-Mercapto-2',3'-dideoxy-NTP were synthesized and tested as DNA chain terminating nucleotides. It is shown that the analogues selectively a nd irreversibly terminate DNA chain elongation by AMV and HIV reverse transcriptase and terminal deoxynucleotidyl transferase, whereas calf thymus alpha DNA polymerase, E. coli DNA polymerase I (Klenow fragment ) and MLV reverse transcriptase do not use the nucleotide analogues as chain terminator substrates.