Table 1. Parameters describing the stability and structure of EphA3 unliganded dimers.

K_diss is the dissociation constant (receptors/μm²), ΔG is the dimerization free energy, Ẽ is the intrinsic FRET efficiency and d is the calculated distance between the fluorescent proteins in the EphA3 dimers. K_diss and Ẽ are determined from a fit of the dimerization model to the FRET data and the uncertainties are the 95% confidence intervals from the fit. ΔG and d are calculated using eqns (6) and (4) respectively. Deletion of the EphA3 SAM domain increases the dissociation constant by an order of magnitude, corresponding to a dimerization free energy change of −1.3±0.3 kcal/mole.

	Kdiss (rec/μm2)	ΔG (kcal/mol)	Ẽ	d (Å)
EphA3	55±16	−5.8±0.2	0.60±0.03	50±1
EphA3 ΔSAM	471±130	−4.5±0.2	0.49±0.04	54±1