Title:Synthesis, Biophysical Characterization, and Anti-HIV-1 Fusion Activity of DNA Quadruplex-based Inhibitors with Dipeptide MT Hook Conjugation
Volume: 19
Issue: 4
Author(s): Liang Xu*, Zeye Han and Hongqian Ren
Affiliation:
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing,China
Keywords:
Oligodeoxynucleotide, quadruplex, MT hook, conjugate, HIV-1, fusion inhibitor.
Abstract:
Background: Human immunodeficiency virus type-1 (HIV-1) infection is the reason for
the epidemic of acquired immunodeficiency syndrome (AIDS). The development of HIV-1 fusion
inhibitors has gained increasing attention as they were found to be effective in the early stage of
HIV-1. DNA G-quadruplex-based inhibitors have been found to interact with HIV-1 envelope glycoprotein,
showing anti–HIV-1 fusion activity. C-peptide-derived molecules with Met-Thr terminal
also showed potent anti-fusion activity; the Met-Thr dipeptide adopted a hook-like structure
(termed MT hook) in the hydrophobic pocket to “anchor” inhibitors to the N-terminal heptad repeat
(NHR) of HIV-1 envelope glycoprotein gp41.
Objective: Our work was aimed to conjugate MT hooks to the 5'-terminal ends of DNA quadruplex-
based inhibitor and demonstrate its biophysical characterization and anti–HIV-1 fusion activity.
Methods: A 6-aminohexanol phosphonamidite was utilized in solid synthesis for the conjunction
of oligodeoxynucleotide and MT dipeptide. Hydrophobic groups were introduced by a nucleoside
analogue from the base site. Circular dichroism spectrum and native polyacrylamide gel electrophoresis
were used to confirm the helix formation. A cell-cell fusion assay was carried out to
test the anti-fusion activity.
Results: The conjugate G1 showed improved anti-cell-cell fusion activity than quadruplex without
MT hook. The MT hook did not affect the oligodeoxynucleotide (ODN) G-quadruplex assembly. It
was also proved that G1 could effectively interfere with endogenous 6-helical bundle (6HB) formation
between the N-terminal heptad repeat N36 (NHR) and the C-terminal heptad repeat C34
(CHR) during virus fusion course.
Conclusion: In this work, a conjugate of DNA-oligopeptide was successfully synthesized. The conjugation
of MT hook did improve the anti-fusion activity of DNA G-quadruplex-based inhibitors.
Our results can provide information regarding structure-activity relationships of DNA helix-based
inhibitors and a reference for the follow-up experimental studies.
