Table 1.

Comparison of experimental and simulated macroscopic pK_as for apo and cCMP-RNase A using the Hill equation and the “apparent pK_a” model.

	His12	His119	Lys41
Apo RNase A
Expt.	5.8a	6.2a	9.0b
Hill Eq.	5.95 (0.14)	6.23 (0.07)	9.27 (0.07)
Expt. (“Apparent” pKa estimate)c	4.9-5.2	6.3-6.9	-
“Apparent” pKa model with H12(B)/H119(A)	5.88 (0.14)	6.27 (0.08)	-
“Apparent” pKa model with K41(B)/H119(A)	-	6.17 (0.21)	8.81 (0.21)
cCMP-RNaseA
Expt. (3′-CMP)	8.0d	7.4d	9.11e
Hill Eq.	7.95 (0.15)	7.17 (0.12)	9.65 (0.16)
Expt. (cCMP “Apparent” pKa)f	8.10	6.30	-
Expt. (cCMP “Apparent” pKa)g	9.0	6.25	-
“Apparent” pKa model with H119(B)/H12(A)	7.92 (0.16)	7.16 (0.12)	-
“Apparent” pKa model with H119(B)/K41(A)	-	7.18 (0.13)	9.64(0.16)

The calculated macroscopic pK_a values using the Hill equation [Eq. (8)] and the “apparent pK_a” model for the apo and cCMP-bound RNase A were compared with the experimental macroscopic and kinetic pK_a (Expt.) values from the literature. Statistical error estimates, shown in parentheses, were obtained as standard deviations derived from values computed from data in 5 ns intervals over the 60 ns of production.

^aTaken from Ref. 33

^bTaken from Ref. 34

^cRange of values estimated from values reported in Ref. 21,39

^dTaken from Ref. 35

^eTaken from Ref. 34

^fTaken from Ref. 38

^gTaken from Ref. 19;

3′-CMP, cCMP are the substrates: 3′-cytidine monophosphate, 2′,3′-cyclic phosphate