FIGURE 3. ITC measurements with wild-type MeTr and N199A variant.
The experiments were performed by titrating 50μm MeTr (as monomer) in 0.1 m buffer, 0.1 m NaCl, 1 mm DTT with 1.5 mm 6S-CH3-H4folate in the same buffer. For wild-type and N199A MeTr, the buffers were MES, pH 5.1, and Tris-HCl, pH 7.6. A, for the N199A variant (measured at pH 5.1), the fit parameters are n = 1.2, K = 1.26 (± 0.04) × 106 m, ΔH = –13200 ± 40 cal/mol, ΔS = –17.1 cal/mol-K. B, for wild-type MeTr (measured at pH 7.6), the fit parameters are n = 1.5, K = 3.01 (± 0.13) × 104 m, ΔH = –8187 ± 209 cal/mol, ΔS = –7.44 cal/mol-K.