THE EFFECT OF CERTAIN N-TRITYLATED PHENYLALANINE CONJUGATES OF AMINO-ADENOSINE-3′,5′-CYCLIC MONOPHOSPHATE ON MOLONEY MURINE LEUKAEMIA VIRUS REVERSE TRANSCRIPTASE ACTIVITY

Moloney murine leukaemia virus (M-MuLV) is a member of the retrovirus family. Its cloned reverse transcriptase (RT), similarly to HIV type 1 reverse transcriptase (HIV-1 RT), exhibits DNA-polymerase and ribonuclease H (RNase H) activities capable of converting the single-stranded retroviral RNA genome into double-stranded DNA. The latter is then integrated into the host chromosome during viral infection. M-MuLV RT is, therefore, an attractive enzyme to help understand mutations in HIV-1 RT and its use in inhibition studies can help facilitate new drug designs. In this study, conjugates consisting of N-trityl derivatives of p-fluoro, p-nitro and p-iodo-DL-phenylalanine were coupled to 8-(6-aminohexyl) amino-adenosine-3',5'-cyclic monophosphate and examined for their effect on DNA synthesis by M-MuLV RT. Synthesis was studied in a system containing poly (rA).oligo d(pT)(15) as a template-primer with [H-3] dTTP. The iodo-derivative, N-trityl-p-iodo-DL-phenylalanine-8-(6-aminohexyl) amino-adenosine-3',5'-cyclic monophosphate was found to be a very active inhibitor of the RI enzyme (IC50 = 1 mu M), while the p-nitro (IC50 = 45 mu M) and p-fluoro (IC50 = 65 mu M) were weak inhibitors. Further work will be aimed at determining the mode of binding of the N-tritylated conjugates and also of various substituted amino acids and short peptides to M-MuLV RI to elucidate the mechanisms of inhibition.