Thermodynamic parameters governing effector binding to <i>Mycobacterium tuberculosis</i> BPL

Titrations were carried out in 10 mM Tris-HCl, ph-7.5 containing 200 mM KCl, 2.5 mM MgCl2 using a VP-ITC calorimeter (Microcal, Inc.,USA). Binding parameters Kb and ΔH were determined b fitting of ITC data to a single-site binding model in the Origin software package. Binding free energies (ΔG) and entropies (ΔS) were calculated using the equation, ΔG = RT lnKb and ΔG = ΔH−TΔS. The values given above represent results of a single titration with each ligand and in multiple titrations the values of Kb and ΔH are reproducible within 2-fold and 1 kcal/mol.