Table 1.

Equilibrium constants (K_BC) for RecBC binding to the non-fluorescent DNA IV to VI series molecules at 25°C.

DNA IVa			DNA Va
3′-(dT)n tail length (n)	KBC (107 M−1) in 10 mM MgCl2	KBC (107 M−1) in 0 mM MgCl2	5′-(dT)n tail length (n)	KBC (107 M−1) in 10 mM MgCl2	KBC (107 M−1) in 0 mM MgCl2
0	1.6 ± 0.3	0.56 ± 0.05	0	1.6 ± 0.3	0.56 ± 0.05
2	4.3 ± 0.4	1.96 ± 0.2	2	2.2 ± 0.4	0.79 ± 0.05
4	18 ± 2	13 ± 2	4	3.8 ± 0.4	1.7 ± 0.3
6	39 ± 3	39 ± 3	6	4.8 ± 0.5	4.6 ± 0.4
8	19 ± 2	19 ± 2	8	4.7 ± 0.4	4.5 ± 0.4
10	8.2 ± 0.9	9.0 ± 0.9	10	5 ± 0.5	4.9 ± 0.3
20	0.82 ± 0.09	0.90 ± 0.06	20	4.7 ± 0.5	4.7 ± 0.4

DNA VI (twin-tails)b
(dT)n tail length (n)	KBC (106 M−1) in 10 mM MgCl2	KBC (106 M−1) in 0 mM MgCl2
6	13 ± 1	13 ± 1

^abuffer M plus 100 mM NaCl and the indicated [MgCl₂]

^bbuffer M plus 750 mM NaCl and the indicated [MgCl₂]