title: Isothermal Titration Calorimetry Measurements of Metal Ions Binding to Proteins.
abstract: ITC measurements involving metal ions are susceptible to a number of competing reactions (oxidation, precipitation, and hydrolysis) and coupled reactions involving the buffer and protons. Stabilization and delivery of the metal ion as a well-defined and well-characterized complex with the buffer, or a specific ligand, can suppress undesired solution chemistry and, depending on the stability of the metal complex, allow accurate measurements of higher affinity protein-binding sites. This requires, however, knowledge of the thermodynamics of formation of the metal complex and accounting for its contribution to the experimentally measured values (KITC and ΔHITC) through a post hoc analysis that provides the condition-independent binding thermodynamics (K, ΔG(o), ΔH, ΔS, and ΔCP). This analysis also quantifies the number of protons that are displaced when the metal ion binds to the protein.
authors.affiliation: Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA.
authors.forename: Colette F
authors.initials: CF
authors.lastname: Quinn
authors.affiliation: Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA.
authors.forename: Margaret C
authors.initials: MC
authors.lastname: Carpenter
authors.affiliation: Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA.
authors.forename: Molly L
authors.initials: ML
authors.lastname: Croteau
authors.affiliation: Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA. Electronic address: dean.wilcox@dartmouth.edu.
authors.forename: Dean E
authors.initials: DE
authors.lastname: Wilcox
mesh_terms: D002151:Calorimetry; D008670:Metals / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*
chemical_list: D008670:Metals; D011506:Proteins
keywords: Binding enthalpy; Buffer competition; Chelation titration; Isothermal titration calorimetry; Metal ions; Proteins