Figure 8.

Binding kinetics of the PSG supramodule and D-CRIPT₁₅. A, PSG (1 μm final concentration) was mixed rapidly in the stopped flow with D-CRIPT₁₅ (10 μm final concentration). A single-exponential function well describes the experimental transient, as shown by comparison of residuals from fit to single- and double-exponential functions. B, the experiment was repeated over a range of D-CRIPT₁₅ concentrations, and k_obs obtained from the fit to a single-exponential function was plotted versus [D-CRIPT₁₅] to obtain k_on^app = (8.4 ± 0.2) × 10⁶ m⁻¹ s⁻¹ (fitting error). C, dissociation of the complex. PSG:D-CRIPT₁₅ (2 and 10 μm) was rapidly mixed with an excess of unlabeled CRIPT (150 μm). The resulting trace was fitted to both single- and double-exponential functions. The residuals from the fits show that the dissociation kinetics follow single exponential kinetics. The average of three experiments using 100, 150, and 200 μm CRIPT, respectively, for displacement yielded k_off^app = 3.5 ± 0.011 s⁻¹ (± S.D.).