Table 2.
CreWT and CreQQ Kinetic Parametersa: Rates of Substrate Disappearance
| reaction | extent, f | A | k1 (× 103 s−1) | k2 (× 103 s−1) | t1/2 (s)b | RLSc |
|---|---|---|---|---|---|---|
| CreWT-LoxPd | 60 ± 6 | 0.42 ± 0.02 | 4.5 ± 1.3 | 32 ± 3 | 48 | first strand exchange |
| LoxTA | 64 ± 3 | 0.81 ± 0.08 | 4.3 ± 1.0 | 22 ± 3 | 119 | HJ resolution |
| LoxATd | 62 ± 10 | 0.87 ± 0.04 | 2.7 ± 0.6 | 35 ± 6 | 234 | HJ resolution |
| LoxGCe | 7 ± 2 | 0.87 ± 0.06 | 2.1 ± 0.2 | 24 ± 2 | 301 | HJ resolution |
| CreQQ-LoxPd | 42 ± 1 | 0.54 ± 0.05 | 14 ± 0.2 | 120 ± 5 | 19 | first strand exchange |
| LoxTA | 60 ± 2 | 0.27 ± 0.05 | 5.1 ± 0.8 | 54 ± 6 | 19 | first strand exchange |
| LoxATd | 48 ± 2 | 0.43 ± 0.01 | 9.0 ± 0.1 | 93 ± 6 | 17 | first strand exchange |
| LoxGC | 55 ± 2 | 0.28 ± 0.03 | 7.0 ± 3.0 | 57 ± 6 | 18 | first strand exchange |
a
The parameters were fit to the biphasic kinetic function as described in Experimental Procedures.
b
Values for t1/2 are calculated based on the averaged curve fits for each reaction (see Figure 4b).
c
The rate-limiting step (“RLS”) occurs either during the first strand cleavage and exchange to form the HJ intermediate (“first strand exchange”) or during HJ isomerization or the second strand exchange to form recombinant products (“HJ resolution”).
d
Data from ref 16.
e
The data were fit to the sequential a → b → c kinetic model described in Experimental Procedures, for comparison with CreWT/LoxGC product formation.