Figure 1.

Competition between TTG1 and GL1 for binding to GL3. (A) Schematic representation of cooperativity between GL1 and TTG1. The K_D of GL1 is adjusted by the cooperativity parameter α as a result of TTG1 bound to GL3. (B) Measurement of GL3-TTG1 binding in presence of GL1 at 2:1 (blue) and 1:1 (red) ratio. The model in A is used to fit the data and estimate α = 0.2. Shaded regions indicate the 95% confidence interval. (C) Measurement of GL3-GL1 binding in presence of TTG1 at 2:1 (blue), 1:1 (red) and 1.8:1 (yellow) ratio. The shaded region indicates 68% confidence interval as determined by the χ ² profile of the estimate for α in the inset. The dashed line in the inset indicates the 95% confidence interval and the dash-dotted line indicates 68% confidence. (D) Fit to the data in C with a function that allows higher order complexes in GL1, given in Equation 25;