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Characterization of human carbonic anhydrase XII stability and inhibitor binding

Vaida Jogaitė1, Asta Zubrienė, Vilma Michailovienė

  • 1Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology, Graičiūno 8, Vilnius LT-02241, Lithuania.

Bioorganic & Medicinal Chemistry
|November 20, 2012
PubMed

Insights

Human carbonic anhydrase XII (CA XII) is an anticancer target. We characterized sulfonamide inhibitor binding thermodynamics, revealing pH and buffer-dependent interactions crucial for designing specific CA XII anticancer drugs.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Pharmacology

Background:

  • Human carbonic anhydrase isozyme XII (CA XII) is a transmembrane protein.
  • CA XII is overexpressed in various human cancers, making it a significant anticancer drug target.
  • Currently, limited compounds specifically target CA XII, necessitating further research into inhibitor design.

Purpose of the Study:

  • To characterize the thermodynamic parameters of sulfonamide inhibitor binding to CA XII.
  • To understand the influence of buffer and pH on inhibitor binding.
  • To provide insights into the structural features and binding mechanisms for developing specific CA XII inhibitors.

Main Methods:

  • Isothermal titration calorimetry (ITC) was employed to measure binding thermodynamics.
  • Fluorescent thermal shift assay (FTSA) was used to assess protein stability and binding.
  • Protonation-deprotonation reactions of active site water and inhibitor groups were analyzed.

Main Results:

  • Sulfonamide binding to CA XII demonstrated significant dependence on buffer composition and pH.
  • Intrinsic thermodynamic parameters (enthalpy, entropy, Gibbs free energy) of binding were determined.
  • CA XII stability was evaluated across different pH conditions and in the presence of various buffers and salts.

Conclusions:

  • The study elucidates the thermodynamic basis of sulfonamide binding to CA XII.
  • Understanding these binding characteristics is essential for the rational design of novel CA XII-specific anticancer agents.
  • The findings highlight the importance of considering solution conditions in drug design targeting CA XII.

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