Table 2.

Thermal denaturation temperatures (T_m) and thermal advantages (TA) of 2′-O-(pyren-1-yl)methylribonucleotide modified probes.^a

ON	Sequence	Tm [ΔTm] (°C)			TAc (°C)
		upper strand vs ssDNA	lower strand vs ssDNA	Invaderb
CSU CSL	5′-UAUGCCATTUGAAA 3′-b-AUACGGTAAACTTT	55.5 [+11.5]	59.0 [+15.0]	44.5 [+0.5]	26.0
CCU CCL	5′-AGCUAUAAGAGUTC 3′-TCGAUAUTCTCAAG-C6NH2	60.5 [+16.0]	62.5 [+18.0]	47.5 [+3.0]	31.0
ESU ESL	5′-AACAGTTCUATCAG 3′-b-TTGUCAAGAUAGUC	61.0 [+16.0]	64.0 [+19.0]	40.0 [−5.0]	40.0
ECU ECL	5′-GCAUGGCTCTUGAT 3′-CGUACCGAGAACTA-C6NH2	65.0 [+13.0]	69.0 [+17.0]	56.0 [+4.0]	26.0
SSU SSL	5′-CACGTTCGGGCAAT 3′-b-GUGCAAGCCCGUTA	72.5 [+15.0]	66.5 [+9.0]	60.5 [+3.0]	21.0
SCU SCL	5′-TCGTUATUGGCGAT 3′-AGCAAUAACCGCUA-C6NH2	66.0 [+14.5]	68.0 [+16.5]	54.5 [+3.0]	28.0

^aΔT_m = change in T_m relative to the corresponding unmodified reference duplexes (T_m = 44.0 °C, 44.5 °C, 45.0 °C, 52.0 °C, 57.5 °C and 51.5 °C for the unmodified reference duplexes of CSU/CSL, CCU/CCL, ESU/ESL, ECU/ECL, SSU/SCL, respectively); thermal denaturation curves were recorded in medium salt buffer ([Na⁺] = 110 mM, [Cl⁻] = 100 mM, pH 7.0 (NaH₂PO₄/Na₂HPO₄)), using 1.0 μM of each strand; see main text for definition of TA. For structures of A, C, G and U, see Fig. 1; “b” and C₆NH₂”, denotes 3′-biotin TEG and 5′-amino-modifier C6 units, respectively.

^bthermal denaturation curves of Invaders display broad transitions.

^cexample of TA calculation: TA (ESU:ESL) = T_m (ESU:ssDNA) + T_m (ESL:ssDNA) – T_m (ESU:ESL) – T_m (reference dsDNA of ESU:ESL) = 61.0 + 64.0 – 40.0 – 45.0 = 40.0 °C