Figure 4.

Observations of binding “diligand” to ecTS. (A) Chemical structure of stable “diligand” as a model for intermediate II in the reaction mechanism (see Figure 1). The fluorine (blue) is a poor leaving group, which stabilizes this intermediate. (B) Schematic of the three liganded states of the TS homodimer (apo, lig₁, lig₂) and a resultant “peak quartet.” Peaks are color coded to correspond with the liganded state (black = apo, blue = saturated) and to discriminate bound (red) and empty (green) subunits of the lig₁ state. (C) Fitting of relative K_d values from quartet peak intensities, as reported in Sapienza et al. (ref 29). (D) Range of ρ values from monte carlo simulations of fit in (C).