Figure 5.

Impact of the hydrophobic contact area onto the dynamics of the NORE1A–Ras interaction. Left panel: Dissociation rate constants k_off for the wt and mutant NORE1A–Ras·mGppNHp complex were determined by stopped-flow measurements using an excess of unlabelled Ras·GppNHp for displacement. A single exponential equation was fitted to the observed fluorescence change to obtain k_off. Right panel: Stopped-flow measurements were performed using pseudo-first-order conditions to determine association rate constants k_on of wt and mutant Ras or NORE1A proteins. The observed association rate constants k_obs were plotted against wt or mutant NORE1A concentration to obtain k_on by linear fitting.