Application of isothermal titration calorimetry in bioinorganic chemistry

Grossoehme, Nicholas E.; Spuches, Anne M.; Wilcox, Dean E.

doi:10.1007/s00775-010-0693-3

Cited by 110 publications

(118 citation statements)

References 22 publications

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“…With these parameters the reaction entropy can be calculated. ITC can also be applied to study the interaction of metal ions with biomolecules (for a recent review see [30]). In our study, we used this approach to examine the interaction of Cu 2+ with DAHK and GHK peptides.…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic study of Cu2+ binding to the DAHK and GHK peptides by isothermal titration calorimetry (ITC) with the weaker competitor glycine

et al. 2011

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The peptides Asp-Ala-His-Lys (DAHK) and Gly-His-Lys (GHK) are naturally occurring copper(II)-chelating motives in human serum and cerebrospinal fluid. Here the sensitive thermodynamic technique isothermal titration calorimetry (ITC) has been used to study the energetics of copper(II) binding to DAHK and GHK peptides in the presence of the weaker ligand glycine as a competitor. DAHK and GHK bind Cu(II) predominantly in a 1:1 stoichiometry with conditional dissociation constants (i.e. at pH 7.4, in the absence of the competing chelators glycine and HEPES buffer) of 2.6 +/-0.4 x 10 -14 M and of 7.0 +/-1.0 x 10 -14 M, respectively. Furthermore, the apparent ΔH values were measured and the number of protons released upon Cu(II) binding was determined by performing experiments in different buffers. This allowed us to determine the conditional ΔG, ΔH, and ΔS, i.e. corrected for the contributions of the weaker ligand glycine and the buffer at pH 7.4. We found that the entropic and enthalpic contributions to the Cu(II)-binding to GHK and DAHK are distinct, with a higher enthalpic contribution for GHK. The obtained thermodynamic parameters correspond well to those in the literature obtained by other techniques, suggesting that the use of the weaker ligand glycine as a competitor in ITC provides accurate data for Cu(II)-binding to high affinity peptides, which cannot be accurately determined without the use of a competitor ligand.3

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Section: Resultsmentioning

confidence: 99%

Thermodynamic study of Cu2+ binding to the DAHK and GHK peptides by isothermal titration calorimetry (ITC) with the weaker competitor glycine

et al. 2011

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“…The observed enthalpy of binding, DH ITC , obtained from ITC titration, can be expressed by Eq. 16, which is based on Hess's law [19]:…”

Section: Resultsmentioning

confidence: 99%

Investigation of metal–buffer interactions using isothermal titration calorimetry

Wyrzykowski

Pilarski²,

Jacewicz

et al. 2012

J Therm Anal Calorim

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Isothermal titration calorimetry (ITC) and potentiometric titration (PT) methods were used to study the interactions of cobalt(II) and nickel(II) ions with buffer substances 2-(N-morpholino)ethanesulfonic acid (Mes), dimethylarsenic acid (Caco), and piperazine-N,N 0 -bis (2-ethanesulfonic acid) (Pipes). Based on the results of PT data, the stability constants were calculated for the metal-buffer complexes (T = 298.15 K, ionic strength I = 100 mM NaClO 4 ). Furthermore, calorimetric measurements (ITC) were run in 100 mM Mes, Caco, and Pipes solutions with pH 6, at 298.15 K. The enthalpies (DH) of the metalbuffer complexation reactions were calculated indirectly by displacement titration using nitrilotriacetic acid (H 3 NTA) as a strong-binding, competitive ligand. Finally, to verify obtained results, the number of protons released by H 3 NTA due to complexation of the cobalt(II) and nickel(II) ions was determined from calorimetric data and compared with results of calculations.

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“…The above derivation does not consider coupled equilibria such as metal-buffer interactions that are often significant in metal solution chemistry [39]. To this end, Eq.…”

Section: Cu 2? Binding To Ab16mentioning

confidence: 99%

“…7 accounts for the presence of Cu 2? -ACES species that are significant at physiological pH, and B represents the deprotonated form of ACES: Table 1 A recently reported method [39] was used to extract buffer-independent binding constants. The large excess of ACES buffer used in this study ensures that most (more than 98%) Cu 2?…”

Section: Cu 2? Binding To Ab16mentioning

confidence: 99%

“…With the advent of highly sensitive calorimeters, isothermal titration calorimetry (ITC) has become an important tool to study biochemical binding processes, including the binding of metal ions to a variety of ligands and proteins [38,39]. In a single titration experiment, one obtains the number of metals bound to the peptide (stoichiometry or n), the binding constant (K), and the heat or change in enthalpy (DH) of binding without the error associated with a van't Hoff analysis.…”

Section: Introductionmentioning

confidence: 99%

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Calorimetric investigation of copper(II) binding to Aβ peptides: thermodynamics of coordination plasticity

et al. 2012

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Metal ions have been shown to play a critical role in β-amyloid (Aβ) neurotoxicity, thus prompting an intense investigation into the formation of metal-Aβ complexes. Isothermal titration calorimetry (ITC) has been widely used to determine binding constants (K) for a variety of metal-protein interactions, including those in metal-Aβ complexes. In this study, ITC was used to more fully quantify the thermodynamics (K, ΔG, ΔH, and TΔS) of Cu(2+) binding to Aβ16, N-acetyl-Aβ16, Aβ28, N-acetyl-Aβ28, and Aβ28 variants (H6A, H13A, H14A) at pH 7.4 and 37 °C. After deconvolution of competing reactions, K for Aβ16 was found to be 1.1 (±0.13) × 10(9) and is in strong agreement with literature values measured under similar conditions. Further, a similar K value was obtained at two additional concentrations of competing ligand, suggesting that ternary complex formation is not significant. The acetylated peptide analogs reveal a marked decrease in the overall free energy upon binding, which is the result of less favorable enthalpic and entropic contributions. Circular dichroism spectroscopy shows conformational changes that are consistent with these results. Most importantly, data for Aβ28 variants lacking a potential Cu(2+)-binding histidine residue reveal that the overall free energy of binding remains constant, which is the result of entropy/enthalpy compensation. These data provide fundamental thermodynamic evidence for coordination plasticity in Cu(2+) binding to Aβ and other intrinsically disordered peptides.

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Application of isothermal titration calorimetry in bioinorganic chemistry

Cited by 110 publications

References 22 publications

Thermodynamic study of Cu2+ binding to the DAHK and GHK peptides by isothermal titration calorimetry (ITC) with the weaker competitor glycine

Thermodynamic study of Cu2+ binding to the DAHK and GHK peptides by isothermal titration calorimetry (ITC) with the weaker competitor glycine

Investigation of metal–buffer interactions using isothermal titration calorimetry

Calorimetric investigation of copper(II) binding to Aβ peptides: thermodynamics of coordination plasticity

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