Thermodynamic and biological evaluation of a thrombin binding aptamer modified with several unlocked nucleic acid (UNA) monomers and a 2′-C-piperazino-UNA monomer

Troels B. Jensen, Jonas Rosager Henriksen, Bjarne E. Rasmussen, Lars M. Rasmussen, Thomas Lars Andresen, Jesper Wengel, Anna Pasternak

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    Thrombin binding aptamer is a DNA 15-mer which forms a G-quadruplex structure and possess promising anticoagulant properties due to specific interactions with thrombin. Herein we present the influence of a single 2′-C-piperazino-UNA residue and UNA residues incorporated in several positions on thermodynamics, kinetics and biological properties of the aptamer. 2′-C-Piperazino-UNA is characterized by more efficient stabilization of quadruplex structure in comparison to regular UNA and increases thermodynamic stability of TBA by 0.28–0.44kcal/mol in a position depending manner with retained quadruplex topology and molecularity. The presence of UNA-U in positions U3, U7, and U12 results in the highest stabilization of G-quadruplex structure (ΔΔG37°=−1.03kcal/mol). On the contrary, the largest destabilization mounting to 1.79kcal/mol was observed when UNA residues were placed in positions U7, G8, and U9. Kinetic studies indicate no strict correlation between thermodynamic stability of modified variants and their binding affinity to thrombin. Most of the studied variants bind thrombin, albeit with decreased affinity in reference to unmodified TBA. Thrombin time assay studies indicate three variants as being as potent as TBA in fibrin clotting inhibition.
    Original languageEnglish
    JournalBioorganic & Medicinal Chemistry
    Volume19
    Issue number16
    Pages (from-to)4739-4745
    ISSN0968-0896
    DOIs
    Publication statusPublished - 2011

    Keywords

    • Unlocked nucleic acid
    • Thermodynamics
    • Isothermal titration calorimetry
    • Thrombin binding aptamer
    • Thrombin time assay

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