Fig. 3.
RNAP−PcopA interaction kinetics and mechanism. (A) Minimal kinetic mechanism. RNAP (R) binds reversibly to PcopA (P, E0 state) to form the dead-end (RPDE, E1 state) and open (RPO, E2 state) complexes that do not interconvert. k’s, kinetic constants; [R], RNAP concentration. (B) Distribution of τ0 for RNAPCy5−PcopACy3@−5 interactions at 2 nM [RNAPCy5]. Solid line is a fit with Nγexp(−γτ); γ = (k1 + k2)[R]; N is a scaling factor. Fitted parameters are in Table 1. k1/k2 = (ratio of observed E0 → E1 and E0 → E2 transitions). (C) Same as B but for τ1. Solid line is a fit with Nk−1exp(−k−1τ). (D) Same as B but for τ2. Solid line is a fit with Nk−2exp(−k−2τ).