Table 1. Analysis of the EMS and AUC Binding Data.

	EMS		AUC
	nonspecific finite lattice modela	competitive specific/nonspecific finite lattice modelb	competitive specific/nonspecific finite lattice modelc	hydrodynamic modelingd
Kns	(7.0 ± 0.2) × 106 M–1	(2.9 ± 0.3) × 106 M–1	(1.7 ± 0.6) × 106 M–1
ω	37 ± 2	9.7 ± 2.6	10 ± 4
Ksp	–	≤6.9 × 109 M–1	(2.0 ± 1.6) × 108 M–1
	–	–	ssp* = 2.59 ± 0.12 S	ssp = 2.36 S
	–	–	⟨sns*⟩ = 3.37 ± 0.04 S	sns = 3.52 S

^aEMS binding data for the cos274, [R3-I1-R2], and [I2-R3-I1] duplexes presented in Figure 4A were simultaneously analyzed (globally fit) according to the nonspecific finite lattice DNA binding model as outlined in Experimental Procedures. The best fit of the ensemble of data is presented as a solid lines in Figure 4A.

^bEMS data for the minimal I1 duplex presented in Figure 4B were fit to the competitive specific/nonspecific finite lattice DNA binding model as outlined in Experimental Procedures. The best fit is presented as a solid line in Figure 4B.

^cSV-AUC binding data for the I1 and R3 minimal duplexes presented in Figure 5 were simultaneously analyzed (globally fit) according to the competitive specific/nonspecific finite lattice DNA binding model and the nonspecific finite lattice DNA binding model, respectively, as oulined in Experimental Procedures. The best fit of the ensemble of data is presented as solid lines in Figure 5C.

^dHydropro was used to determine the theoretical sedimentation coefficients for the specific IHF-I1 complex (s_sp based on high-resolution structural data⁴³) and the nonspecific IHF–R3 complex [s_ns based on a structural model of three IHF dimers bound to the 27 bp duplex (Supporting Information)].