Table 2. Binding of guanine nucleotides and analogues to WT and variants of eEFSec.

Ligand	Protein	Kd (μM)	ΔH (kcal mol−1)	ΔS (cal mol−1 per deg)
GDP	WT	0.19±0.05	−17.19±0.30	−26.90
	T48A	0.24±0.05	−16.11±0.25	−23.70
	D92A	1.50±0.13	−9.41±0.13	−4.90
	H96A	1.30±0.24	−18.14±0.45	−33.90
GTP	WT	1.21±0.26	−20.57±0.67	−41.90
	T48A	1.82±0.11	−17.41±0.18	−32.10
	D92A	8.47±0.49	−9.88±0.49	−9.92
	H96A	1.60±0.75	−19.06±1.37	−37.40
GDPNP	WT	1.20±0.47	−16.05±0.77	−26.70
GDPCP	WT	1.85±0.24	−20.23±0.46	−41.60
GTPγS	WT	0.48±0.06	−16.87±0.19	−27.70

K_d, dissociation constant; ΔH, enthalpy change; ΔS, entropy change.

Human eEFSec contains a single nucleotide-binding site; N=1.