Table 3.

Electrostatic energies of interaction between histidines and other ionizable groups (ΔGij) calculated at 0.10 M ionic strength with the FDPB methoda

	Contact	rij (Å)b	ΔGij (kcal/mole)
His-8	Glu-10	4.32	1.22
	Arg-81	8.13	0.43
	Glu-75	8.50	0.40
	Lys-28	8.20	0.36
	Lys-9	9.07	0.29
	Glu-73	9.86	0.28
His-46	Glu-52	4.94	1.07
	Glu-43	5.33	0.93
	Lys-49	5.75	0.64
	Asp-40	9.73	0.41
	Asp-21	10.27	0.37
	Lys-48	7.78	0.35
	Arg-35	11.09	0.34
	Asp-19	10.54	0.28
	Arg-87	11.86	0.27
His-121	Glu-75	6.07	0.92
	His-124	6.30	0.76
	Asp-77	7.27	0.73
	Lys-9	8.14	0.49
	Lys-78	8.77	0.36
	Glu-101	9.92	0.34
	Glu-122	10.49	0.27
His-124	Glu-101	4.34	1.33
	His-121	6.30	0.76
	Glu-75	10.35	0.35
	Lys-9	9.49	0.32
	Lys-127	9.49	0.28
	Arg-105	10.81	0.26

^a Interactions with |ΔG_ij| >0.25 kcal/mole are included.

^b Distances measured between Nδ1 of His-8 and His-121, Nɛ2 of His-46 and His-124, and Nζ of Lyz, Cζ of Arg, Cɛ1 of His, Cγ of Asp, Cδ of Glu. The lstn structure was used.