TABLE 2.

DNA length dependence of the DNA binding properties of RecQ

Shown are 5 °C, 0.5 μm RecQ Trp fluorescence stopped-flow data. Nomenclature of parameters refers to Fig. 1G. All parameters with dimensions involving concentration are specified based on DNA concentrations expressed in constituent nucleotide units (nt).

Parameter	Source data	dT18	dT54	dT90	poly(dT)
Total DNA-induced quench (%, relative to DNA-free state)	Amplitudes	31 ± 2	30 ± 2	42 ± 2	44 ± 2
Contribution of slow phase (% of total quench)	Amplitudes	9 ± 4	17 ± 4	23 ± 4	43 ± 5
k1 (μm−1 s−1)	Binding kinetics	2.8 ± 0.4	2.4 ± 0.4	2.5 ± 0.2	2.3 ± 0.7
k−1 (s−1)	Binding kinetics	35 ± 14	29 ± 11	21 ± 16	< 10
K1 (μm)	k−1/k1	13 ± 7	12 ± 7	8.4 ± 7.1	< 5
	Amplitudes	55 ± 27	49 ± 8	27 ± 8	23 ± 14
k2 + k−2 (s−1)	Binding kinetics	15 ± 3	16 ± 4	17 ± 16	> 20
Keq (μm)	Amplitudes	36 ± 16	16 ± 3a	9.0 ± 2.0a	8.0 ± 2.0a

^a Apparent K_eq value limited by RecQ concentration and DNA binding stoichiometry (cf. Table 1), representing an upper bound for K_eq.