Iminodipropionic Acid as the Leaving Group for DNA Polymerization by HIV-1 Reverse Transcriptase

Authors

  • Xiao-Ping Song,

    1. Rega Institute, Laboratory of Medicinal Chemistry, Katholieke Universiteit Leuven, Minderbroederstraat 10, 3000 Leuven (Belgium)
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  • Dr. Camille Bouillon,

    1. Rega Institute, Laboratory of Medicinal Chemistry, Katholieke Universiteit Leuven, Minderbroederstraat 10, 3000 Leuven (Belgium)
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  • Prof. Dr. Eveline Lescrinier,

    1. Rega Institute, Laboratory of Medicinal Chemistry, Katholieke Universiteit Leuven, Minderbroederstraat 10, 3000 Leuven (Belgium)
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  • Prof. Dr. Piet Herdewijn

    Corresponding author
    1. Rega Institute, Laboratory of Medicinal Chemistry, Katholieke Universiteit Leuven, Minderbroederstraat 10, 3000 Leuven (Belgium)
    • Rega Institute, Laboratory of Medicinal Chemistry, Katholieke Universiteit Leuven, Minderbroederstraat 10, 3000 Leuven (Belgium)
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Abstract

Previous studies have demonstrated that some selected amino monoacids and amino diacids can function as leaving groups in the polymerase-catalyzed incorporation of deoxynucleotides into DNA. Among these, the iminodiacetic acid phosphoramidate of deoxyadenosine monophosphate (IDA-dAMP) represents an interesting example, as it could overcome some of the problems observed when using L-aspartic acid as the leaving group, that is, poor chain elongation. We have now synthesized and evaluated a series of IDA-dAMP analogues that bear either an extended aliphatic chain in the amino acid function, or a phosphonic acid moiety (substituting for the carboxylic acid function). Among these compounds, the nucleotide with an iminodipropionic acid leaving group (IDP-dAMP) was identified as the best substrate; the excellent single incorporation (91 % conversion to a P+1 strand at 50 μM) was at a substrate concentration ten times lower than that used for IDA-dAMP). This nucleotide also presented improved kinetics and elongation capability compared to IDA-dAMP. The analogues with T, G, and C base moieties were also investigated for their incorporation ability with HIV-1 RT. The incorporation efficiency was found to decrease in the order A>T>G>C. The properties of the iminodipropionic acid as the leaving group surpass those of previously evaluated leaving groups; this acid will be a prime candidate for in vivo testing.

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