Table 1.

Dissociation constant of antibodies to alternative conformations of the α_L I domain

I domain	KD, nM
	Mg2+		EDTA
	AL-57	MHM24	AL-57	MHM24
WT	ND	1.9 ± 0.4	ND	7.8 ± 0.5
IA	4,700 ± 3,200*	2.0 ± 0.0	ND	4.6 ± 0.1
HA	23 ± 16	6.3 ± 0.2	ND	22 ± 0.0

SPR analysis was performed by using a BIAcore 3000 instrument. The I domains (IA, L161C/F299C mutant; HA, K287C/K294C mutant) were perfused onto antibodies immobilized on a CM-5 chip in buffer containing 1 mM Mg²⁺or 10 mM EDTA at a flow rate of 20 μl/min at room temperature. The data were fit by using a parallel reactions model plus drift to account for baseline offset, and K_D was calculated as k_off/k_on. Data are means ± SEM of at least three independent experiments. ND, binding not detected.

*Determined by steady-state analysis.