Iminodipropionic acid as the leaving group for DNA polymerization by HIV-1 reverse transcriptase

Area of Science:

• Biochemistry
• Molecular Biology
• Nucleic Acid Chemistry

Background:

• Amino acids and diacids can act as leaving groups in polymerase-catalyzed DNA synthesis.
• Iminodiacetic acid phosphoramidate of deoxyadenosine monophosphate (IDA-dAMP) showed potential but had limitations in chain elongation.
• L-aspartic acid as a leaving group also suffered from poor chain elongation.

Purpose of the Study:

• To synthesize and evaluate novel IDA-dAMP analogues with modified leaving groups.
• To improve the efficiency and elongation capability of polymerase-catalyzed nucleotide incorporation.
• To investigate the substrate preference and incorporation efficiency of these analogues with HIV-1 Reverse Transcriptase.

Main Methods:

• Synthesis of IDA-dAMP analogues with extended aliphatic chains or phosphonic acid moieties.
• Evaluation of nucleotide incorporation using polymerase chain reactions.
• Kinetic analysis and assessment of chain elongation capability.
• Testing incorporation efficiency with various base moieties (A, T, G, C) using HIV-1 RT.

Main Results:

• The nucleotide with an iminodipropionic acid leaving group (IDP-dAMP) demonstrated superior performance.
• IDP-dAMP achieved 91% conversion to a P+1 strand at 50 μM, a ten-fold lower concentration than IDA-dAMP.
• IDP-dAMP exhibited improved kinetics and elongation compared to IDA-dAMP.
• Incorporation efficiency followed the order A>T>G>C with HIV-1 RT.

Conclusions:

• Iminodipropionic acid is a highly effective leaving group for polymerase-catalyzed DNA synthesis.
• IDP-dAMP offers significant advantages over previous leaving groups, including enhanced incorporation and elongation.
• This novel nucleotide is a promising candidate for in vivo applications in DNA synthesis and related technologies.