Title: Isothermal Titration Calorimetry Measurements of Metal Ions Binding to Proteins.
Authors: Quinn, Colette F; Carpenter, Margaret C; Croteau, Molly L; Wilcox, Dean E
Published In Methods Enzymol, (2016)
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.
PubMed ID: 26794348
MeSH Terms: Calorimetry*; Metals/metabolism*; Protein Binding; Proteins/metabolism*