. Author manuscript; available in PMC: 2009 Oct 28.

Published in final edited form as: Biochemistry. 2008 Oct 1;47(43):11285–11299. doi: 10.1021/bi801185b

TABLE 3. NaCl dependence of Fcα and mIgA1 κ, λ and Mce binding to FcαRI.

Slopes (SK_obs) for each binding event were determined by fitting log K_A (derived from kinetic rate constants) to a linear regression model. The electrostatic component of the Gibbs free energy of binding (ΔG_elec/ΔG) was determined by comparing the ΔG at 10mM with that at 1M NaCl. ΔG was determined using the formula ΔG= − RTlnK_A where K_A is the association constant, R is the gas constant in cal (K⁻¹ mol⁻¹), and T is the temperature in Kelvin.

	High affinity site		Low affinity site

	SK_obs	ΔG_elec/ΔG	SK_obs	ΔG_elec/ΔG
Fcα	−0.32	8.2%	−0.36	9.3%
mIgA1κ	−0.47	12%	−0.53	15%
Deglycosylated mIgA1κ	−0.45	11%	−0.51	14%
mIgA1λ	−0.51	12%	−0.51	14%
mIgA1_Mce	−0.60	15%	−0.42	11%