Table 2. Apparent equilibrium dissociation constants (KD) for the Sso7d mutants.
| Sso7d mutant | KD (pH 7.4) (nM) | KD (pH 4.5) (nM) |
| Sso7d-hFc | 400 (366–437) | 506 (439–628) |
| Sso7d-his-hFc | 1647 (1337–3000) | N.D.a |
| Sso7d-ev-hFc | 5280 (4500–6700) | N.D.a |
For each mutant, data from at least two independent experiments were fit globally to a four parameter logistic model using non-linear least squares regression for estimation of KD. The corresponding 68% confidence intervals are shown in parentheses.
a
Not determined. The binding isotherm at pH 4.5 did not reach saturation even with 20–30 µM concentration of Sso7d-his-hFc and Sso7d-ev-hFc; consequently, an apparent KD for the binding interaction at pH 4.5 could not be calculated.