Table 3.

Comparison of binding kinetics of AL-57 and ICAM-1

I domain	kon, M−1·s−1 × 10−3		koff, s−1 × 102		KD, nM
	AL-57*	ICAM-1†	AL-57*	ICAM-1†	AL-57*	ICAM-1†
WT	ND	3.1 ± 0.1	ND	460 ± 36	ND	1,500,000 ± 200,000
IA	16.6 ± 13.6	133 ± 10	5.4 ± 5.2	43 ± 7	4,700 ± 3,200	3,000 ± 440
HA	2.1 ± 0.7	115 ± 7	0.0055 ± 0.0057	1.4 ± 0.1	23 ± 16	150 ± 16

Binding kinetics to the alternative conformations of the α_L I domain (IA, L161C/F299C mutant; HA, K287C/K294C mutant) was measured by SPR with a BIAcore instrument in the presence of 1 mM MgCl₂.

*For binding to the IA I domain, k_on and k_off were obtained by curve-fitting using a 1:1 binding model. K_D was calculated by a Scatchard plot using binding at steady state. For binding to the HA I domain, k_on and k_off were obtained by using a parallel reactions model plus drift to account for baseline offset, and K_D was calculated by k_off/k_on. Data are means ± SEM of at least three independent experiments. ND, binding not detected.

^†Data are from ref. 31.