Guanine α-carboxy nucleoside phosphonate (G-α-CNP) shows a different inhibitory kinetic profile against the DNA polymerases of human immunodeficiency virus (HIV) and herpes viruses

Abstract

α-Carboxy nucleoside phosphonates (α-CNPs) are modified nucleotides that represent a novel class of nucleotide-competing reverse transcriptase (RT) inhibitors (NcRTIs). They were designed to act directly against HIV-1 RT without the need for prior activation (phosphorylation). In this respect, they differ from the nucleoside or nucleotide RTIs [N(t)RTIs] that require conversion to their triphosphate forms before being inhibitory to HIV-1 RT. The guanine derivative (G-α-CNP) has now been synthesized and investigated for the first time. The (L)-(+)-enantiomer of G-α-CNP directly and competitively inhibits HIV-1 RT by interacting with the substrate active site of the enzyme. The (D)-(-)-enantiomer proved inactive against HIV-1 RT. In contrast, the (+)- and (-)-enantiomers of G-α-CNP inhibited herpes (i.e. HSV-1, HCMV) DNA polymerases in a non- or uncompetitive manner, strongly indicating interaction of the (L)-(+)- and the (D)-(-)-G-α-CNPs at a location different from the polymerase substrate active site of the herpes enzymes. Such entirely different inhibition profile of viral polymerases is unprecedented for a single antiviral drug molecule. Moreover, within the class of α-CNPs, subtle differences in their sensitivity to mutant HIV-1 RT enzymes were observed depending on the nature of the nucleobase in the α-CNP molecules. The unique properties of the α-CNPs make this class of compounds, including G-α-CNP, direct acting inhibitors of multiple viral DNA polymerases.

Keywords: (1R,4S)-(−)-cis-4-acetoxy-2-cyclopenten-1-ol (PubChem CID: 9855498); (1S,4R)-(+)-cis-4-acetoxy-2-cyclopenten-1-ol (PubChem CID: 10154103); (NH(4))(2)SO(4) (PubChem CID: 22921); Bromophenol blue (PubChem CID: 8272); Dithiothreitol (PubChem CID: 446094); EDTA (PubChem CID: 6049); Ethanol (PubChem CID: 702); Formamide (PubChem CID: 713); Glutathione (PubChem CID: 124886); Glycerol (PubChem CID: 753); HIV reverse transcriptase; Herpes DNA polymerase; KCl (PubChem CID: 4873); MgCl(2) (PubChem CID: 5360315); NaCl (PubChem CID: 5234); Nucleoside/nucleotide analogues; Nucleotide competing RT inhibitor; Polyacrylamide (PubChem CID: 6579); Sodium cacodylate (PubChem CID: 2724247); Sodium pyrophosphate (Na(4)P(2)O(7)) (PubChem CID: 24003); Trichloroacetic acid (PubChem CID: 6421); Tris (PubChem CID: 6503); Triton X-100 (PubChem CID: 5590); α-Carboxy nucleoside phosphonates.