Table 1.

T_m data (°C, 260 nm) of duplexes of 5′-AUGCUXAGUCGA-3′ with 5′-UCGACUYAGCAU-3′ (RNA) or 5′-TCGACTYAGCAT-3′ (DNA) as complement; duplex concentration: 2 µM in 10 mM NaH₂PO₄, 150 mM NaCl, pH 7.0

X	RNA complement (Y)				DNA complement (Y)
	rG	rA	rC	rU	dG	dA	dC	dT
rC	65.7	47.8	45.6	46.0	49.9	28.4	26.7	27.6
5-nbnOrC	61.8	47.1	44.8	44.9	43.6	31.3	28.1	28.3
5-HOrC, Tm1 Tm2	65.2 47.7	47.4	44.0	44.6	48.6 25.9	27.2	25.4	25.4
rU	54.6	59.2	–	–	32.0	42.3	–	–
5-HOrUa	54.2	58.8	–	–	32.5	42.6	–	–

^aSynthesized in analogy to known methods (15).