Table 1.

Duplex stability and base pairing specificity of m⁴C and m⁴₂C in a 12-mer RNA duplex [5′-GGACUXCUGCAG-3′ & 3′-CCUGAYGACGUC-5′] (X pairs with Y)

	Base Pairs		T m	△Tm	–△G°
Entry	X	Y	(°C)a	(°C)b	(kcal/mol)c
1	C	G	69.6		20.6
2	C	A	54.2	–15.4	14.0
3	C	U	52.9	16.7	14.3
4	C	C	50.7	18.9	12.4
5	m4C	G	67.6		14.2
6	m4C	A	50.1	17.5	11.2
7	m4C	U	49.4	18.2	11.5
8	m4C	C	47.1	20.5	10.4
9	m42C	G	54.1		11.1
10	m42C	A	50.0	4.1	11.4
11	m42C	U	47.6	6.5	10.6
12	m42C	C	47.8	6.3	10.6

^aThe T_ms were measured in sodium phosphate (10 mM, pH 7.0) buffer containing 100 mM NaCl, T_m values reported are the averages of four measurements.

^b△T_m values are relative to the duplexes with only Watson–Crick pairs.

^cObtained by non-linear curve fitting using Meltwin 3.5 (49).