Repeatability, precision, and accuracy of the enthalpies and Gibbs energies of a protein–ligand binding reaction measured by isothermal titration calorimetry

Vaida Paketurytė, Vaida Linkuvienė, Georg Krainer, Wen Yih Chen, Daumantas Matulis

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

In rational drug design, it is important to determine accurately and with high precision the binding constant (the affinity or the change in Gibbs energy, ∆G), the change in enthalpy (ΔH), and the entropy change upon small molecule drug binding to a disease-related target protein. These thermodynamic parameters of the protein–ligand association reaction are usually determined by isothermal titration calorimetry (ITC). Here, the repeatability, precision, and accuracy of the measurement of the affinity and the change in enthalpy upon acetazolamide (AZM) interaction with human carbonic anhydrase II (CA II) are discussed based on the measurements using several ITC instruments. The AZM–CA II reaction was performed at decreasing protein–ligand concentrations until the determination of ∆G and ΔH was not possible, indicating a lower limit for accuracy. To obtain the confidence intervals (CI) of the ∆G and ΔH of AZM binding to CA II, the binding reaction was repeated numerous times at the optimal concentration of 10 µM and 25 °C temperature. The CI (at a confidence level α = 0.95) for ΔH = − 51.2 ± 1.0 kJ/mol and ∆G = − 45.4 ± 0.5 kJ/mol was determined by averaging the results of multiple repeats.

Original languageEnglish
Pages (from-to)139-152
Number of pages14
JournalEuropean Biophysics Journal
Volume48
Issue number2
DOIs
StatePublished - 4 Mar 2019

Keywords

  • Accuracy
  • Isothermal titration calorimetry
  • NITPIC software
  • Precision
  • Repeatability
  • SEDPHAT software

Fingerprint

Dive into the research topics of 'Repeatability, precision, and accuracy of the enthalpies and Gibbs energies of a protein–ligand binding reaction measured by isothermal titration calorimetry'. Together they form a unique fingerprint.

Cite this