Table 2.

Binding of M-modified PNA to RNA hairpins.^[a]

PNA	HRP1 (G-C)	HRP2 (A-U)	HRP3 (C-G)	HRP4 (U-A)
PNA4[b]	8.4	0.04	0.05	0.02
PNA5[c]	2.0	<0.001[d]	NB[e]	NB[e]
PNA6[c]	NB[e]	0.4	NB[e]	NB[e]

^[a]Association constants K_a × 10⁷ M⁻¹.

^[b]From ref. 4, in 100 mM sodium acetate buffer, pH 5.5 at 25 °C.

^[c]In phosphate buffer, pH 7.4 at 37 °C.

^[d]Highest estimate; the low binding prevented more accurate curve fit.

^[e]NB – no binding, K_a < 10³.