TABLE 2.

Pairwise site-site interactions W_μν, the total influence of the neighboring sites calculated as a sum of all pairwise site-site interactions and the resulting apparent pK_a values calculated according to Eq. 7 used in the two-state model

Site ν →	C18	C21	C22	C7			pKapp
Site μ↓	Triplex
C18		0.10	0.03	0.18	0.33	0.32	8.05
C21	0.10		1.10	0.02	1.22	1.23	8.23
C22	0.03	1.08		0.01	1.13	1.13	7.88
C7	0.18	0.02	0.01		0.21	0.23	7.49
	Hairpin
C18		0.07	0.03	3.87 × 10−5	0.10	0.10	5.13
C21	0.07		0.57	1.00 × 10−4	0.64	0.63	4.72
C22	0.03	0.58		1.00 × 10−4	0.61	0.61	4.87
C7	3.60 × 10−5	1.01 × 10−4	1.40 × 10−4		2.7 × 10−4	3 × 10−3	4.15

All values are given in pH units.