. Author manuscript; available in PMC: 2015 Jun 1.

Published in final edited form as: DNA Repair (Amst). 2014 Apr 18;18:18–30. doi: 10.1016/j.dnarep.2014.03.032

Table 2.

Kinetic Parameters of Msh2-Msh3 ATP hydrolysis in the presence of homoduplex, MMR and 3′ NHTR DNA substrates.

1:1 ratio	No DNA	Homoduplex DNA	+ 8 loop substrate	Splayed Y substrate	3′flap substrate
V_max (nM/min) ^a	1060 ± 56	923 ± 25	1465 ± 20	1400 ± 23	1305 ± 88
K_m (μM) ^b	842 ± 132	95.4 ± 3.0	8.4 ± 2.1	7.9 ± 1.4	7.2 ± 2.5
k_cat (min⁻¹) ^c	21.2	18.5	29.3	28	26.1
k_cat/K_m (min⁻¹μM⁻¹)	0.025	0.19	3.5	3.5	3.6
Relative to no DNA ^d	1	7.4	134	136	144
Hill co-efficient ^e	1.1 ± 0.2	0.42 ± 0.07	1.1 ± 0.2	0.6 ± 0.1	0.6 ± 0.2

1:5 ratio
V_max (nM/min) ^a	1060 ± 56	500 ± 40	800 ± 60	700 ± 30	712 ± 32
K_m (μM) ^b	842 ± 132	29.6 ± 4.1	23.9 ± 5.1	33.9 ± 6.4	45.1 ± 7.3
k_cat (min⁻¹) ^c	21.2	10.8	16.0	14.0	14.2
k_cat/K_m (min⁻¹μM⁻¹)	0.025	0.34	0.67	0.41	0.3
Relative to no DNA ^d	1	13.6	26.8	16.4	12.4
Hill co-efficient ^e	1.1 ± 0.2	0.3 ± 0.07	1.2 ± 0.2	0.9 ± 0.1	0.8 ± 0.2

1:10 ratio
V_max (nM/min) ^a	1060 ± 56	600 ± 40	900 ± 60	900 ± 30	ND ^f
K_m (μM) ^b	842 ± 132	25.2 ± 2.1	71.3 ± 4.1	25.3 ± 6.4	ND
k_cat (min⁻¹) ^c	21.2	12	18	18
k_cat/K_m (min⁻¹μM⁻¹)	0.025	0.5	0.25	0.71
Relative to no DNA ^d	1	20	10	28.4
Hill co-efficient ^e	1.1 ± 0.2	0.32 ± 0.06	1.0 ± 0.15	1.1 ± 0.11	ND

Maximum rate of ATP hydrolysis when data fit to Michaelis-Menten or Hill equation. Errors represent standard error of the mean.

Dissociation constant determined as the concentration of ATP at half maximal ATP hydrolysis rate data fit to Michaelis-Menten or Hill equation. Errors represent standard error of the mean.

Ratio of V_max and concentration of protein

k_cat/K_m of Msh2-Msh3 in the presence of DNA substrate relative to the absence of DNA

Determined when data fit to Hill equation

ND = Not determined