Experimental studies of protein binding affinity by different methods.

Protein-protein binding is central to most protein functions; convenient assays of binding affinity are thus invaluable for elucidating mechanisms of biological processes. We are carrying out different assays on the binding of the 12 kD FK506-binding protein (FKBP12) with target peptides. The methods include affinity chromatography, isothermal titration calorimetry, and fluorescence spectroscopy. The goal is to identify a convenient protocol for identifying peptides that form part of the binding site on the target protein of FKBP12. FKBP12 is a multiple-function protein. For example, it regulates the ryanodine receptor, a calcium release channel implicated in excitation-contraction coupling. Our approach is expected to have wide applicability in identifying target peptides.