Table 3.

Kinetic parameters for binding of bNAb VRC01, bNAb b12, sCD4, and GL-VRC01 with full-length WT gp120, OD_EC, and ΔG14-OD_EC as determined by SPR studies

k_on is association rate; k_off is dissociation rate; K_D is equilibrium dissociation constant determined using SPR; S.D. is standard deviation for the data from two independent experiments; bNAb is broadly neutralizing antibody; GL is germline. OD_EC and ΔG14-OD_EC were purified from E. coli.

Ligand	Analyte	kon	koff	KD ±S.D.
		m−1 s−1	s−1	nm
VRC01	WT gp120	3.3 × 104	8.7 × 10−4	26 ± 5
	ODEC	3.7 × 104	1.3 × 10−2	359 ± 55
	ΔG14-ODEC	5.6 × 104	3.83 × 10−3	47 ± 17
b12	WT gp120	3.5 × 104	1.7 × 10−3	49 ± 5
	ODEC	1.7 × 104	2.7 × 10−3	153 ± 17
	ΔG14-ODEC	1.1 × 105	1.8 × 10−3	16 ± 1
sCD4	WT gp120	2.3 × 104	3.3 × 10−4	15 ± 4
	ODEC	1.9 × 104	4.2 × 10−3	219 ± 11
	ΔG14-ODEC	1.1 × 105	1.5 × 10−3	15 ± 3
GL-VRC01	WT gp120	–a	–a	–a
	ODEC	3.3 × 105	1.3 × 10−3	4 ± 1
	ΔG14-ODEC	1.4 × 105	1.2 × 10−3	9 ± 2

^a No detectable binding was noted.