Table 1 Kinetic parameters determined with maximum likelihood analysis of single-molecule FRET experiments

From: A proline switch explains kinetic heterogeneity in a coupled folding and binding reaction

Immobilized protein

k′on,1 = kon,1·cligand (s−1)a

k′on,2 = kon,2· cligand (s−1)a

koff,1 (s−1)

koff,2 (s−1)

cligand (nM)b

kon,1 (108 M−1s−1)c

kon,2 (108 M−1s−1)c

k12 (s−1)

k21 (s−1)

NCBD

6.0 ± 0.2

3.0 ± 0.5

7.3 ± 0.3

30 ± 3

65

0.93 ± 0.06

0.46 ± 0.08

0.04 ± 0.01

0.07 ± 0.01

ACTR

3.3 ± 0.3

1.6 ± 0.3

5.6 ± 0.5

30 ± 6

17

3.2 ± 0.5

2.5 ± 0.6

n.a.

n.a.

NCBD P20A

5.1 ± 0.2

n.a.

23 ± 1

n.a.

65

0.78 ± 0.05

n.a.

n.a.

n.a.

  1. Errors are the standard deviations of ten bootstrapping trials if not stated otherwise
  2. n.a., not applicable
  3. aPseudo-first-order association rate coefficient observed in the time traces. The second-order association rate coefficient is calculated based on the ligand concentration cligand measured by FCS in solution (see Methods)
  4. bConcentrations of the acceptor-labeled ligand were determined using FCS (see Methods). An uncertainty of ±5% was estimated from two independent measurements conducted before and after recording the time traces
  5. cSecond-order association rate coefficient calculated from the pseudo-first-order association rate coefficient based on the ligand concentration, cligand, measured by FCS in solution (see Methods). Uncertainty from propagating the error of \(k_{{\mathrm{on}}}^\prime\) and the ligand concentration. The error for immobilized ACTR is greater owing to the greater uncertainty in the relative populations of NCBD1 and NCBD2, p1 and p2: p1 = k21/(k12 + k21) and p2 = k12/(k12 + k21)
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