Table 1. Thermal Denaturation Transitions of All Possible Duplex Combinations, Recorded at 260 nm^a.

entry	duplex	Tm	Tm2
1	1:5	62.5 ± 0.4
2	2:5	59.2 ± 2.1
3	3:5	56.1 ± 1.2
4	4:5	47.1 ± 5.6	23.4 ± 2.6
5	1:6	55.4 ± 0.6
6	1:7	47.1 ± 1.1	26.1 ± 1
7	2:6	50.9 ± 1.6	< 33
8	2:7		25.1 ± 0.6
9	3:6	54.4 ± 2.4	< 28
10	3:7		< 24
11	4:7		< 25

^aAll measurements were carried out in triplicate. Samples of all traces are provided within Supporting Information (Figure S26); entries with a < sign did not display a clear sigmoidal shape. [RNA duplex] = 2.5 μM, [NaCl] 10 mM, [MgCl₂] = 5 mM, [Na₃PO₄] = 10 mM, pH 7.2.