Table 2. Energetics of the alignment between μ and E in solution.

Structural class	Average dipole energy* 〈-(μ·E)〉, kcal·mol-1		Average field† 〈|E|〉, kcal·mol-1·e-1·Å-1
	Neutral‡	BEM§	Neutral‡	BEM§
α	-1.11 (-4.72)	-1.28 (-4.97)	2.52 (5.28)	2.89 (5.52)
β	-0.42 (-1.47)	-0.45 (-1.53)	1.12 (1.96)	1.24 (2.00)
Λ	-0.19 (-1.98)	-0.29 (-2.18)	3.45 (4.84)	3.79 (5.05)

The set of 22 proteins listed in Table 1 was used for these computations.

^*Values were computed as (1/N) Σ_i^N (-|μ_i(r_i)||E_i(r_i)| cos θ_i), with N being the number of μs contained in the particular structural class (values of N for the α, β, and Λ classes are 266, 119, and 636, respectively). In each column, two values are listed for each structural class; the first one corresponds to calculations with the ECEPP/3 charge set, the second one, in parentheses, corresponds to calculations with the PARSE charge set. The average values of μ are 0.54 eÅ and 1.07 eÅ, (1eÅ = 4.8 Debye) for the ECEPP and PARSE sets, respectively.

^†Values were computed as (1/N) Σ_i^N|E_i(r_i)|. See item * for additional explanation.

^‡Values were computed assuming a neutral charge distribution.

^§Values were computed assuming the BEM charge distribution.