Table 2.

Thermal Melting Temperatures (T_m) of IQ-, AF-, and AAF-Modified Oligonucleotides

oligonucleotide a		Tm (Tm)b
		IQc	AFc	AAFd
a	5 ′ -GGC AGG TGG TG-3 ′ (1)	51° (−9°)e
	3 ′ -CCG TCC ACC AC-5 ′
b	5 ′ -CTC GGC GCC ATC-3 ′ (2)	58° (−7°)f	57° (−8°)f
	3 ′ -GAG CCG CGG TAG-5 ′
c	5 ′ -CTC GGC GCC ATC-3 ′ (3)	60° (−5°)f	56° (−9°)f
	3 ′ -GAG CCG CGG TAG-5 ′
d	5 ′ -CTC GGC GCC ATC-3 ′ (4)	61°(−4°)e	52°(−13°)f
	3 ′ -GAG CCG CGG TAG-5 ′
e	5 ′ -ACC GGC GCC ACA-3 ′			51° (−10°)g
	3 ′ -TGG CCG CGG TGT-5 ′
f	5 ′ -ACC GGC GCC ACA-3 ′			48° (−13°)g
	3 ′ -TGG CCG CGG TGT-5 ′
g	5 ′ -ACC GGC GCC ACA-3 ′			48° (−13°)g
	3 ′ -TGG CCG CGG TGT-5 ′
h	5 ′ -CTC GGC GCC ATC-3 ′ (4)	48°(+10°)e	44° (+6°)f
	3 ′ -GAG CC- -GG TAG-5 ′
i	5 ′ -ACC GGC GCC ACA-3 ′ (4)			49° (+15°)g
	3 ′ -TGG CC- -GG TGT-5 ′
j	5 ′ -CTC GGC GCC ATC-3 ′ (4)			55° (+4°)f
	3 ′ -GAG CCG -GG TAG-5 ′

^aG is the C8-modified dGuo.

^bΔT_m= T_m (modified) — T_m (unmodified). The T_m values for the unmodified Ras-12 (entry a, 11-mer), our NarI (entries b—d, 12-mer), and Fuchs’ NarI (entries e—g, 12-mer) oligonucleotides were 60, 65, and 61 °C, respectively. The T_m values for our unmodified NarI (entry h) and Fuch’s unmodified NarI (entry i) oligonucleotide opposite a two-base deletion were 38 and 34 °C, respectively. The T_m values for our unmodified NarI (entry j) oligonucleotide opposite a one-base deletion was 51 °C.

^cConditions: 10 mM phosphate buffer (pH 7.0) containing 100 mM NaCl, 0.05 mM EDTA, and 0.5 A₂₆₀/mL of each oligonucleotide. The temperature was raised 1 °C min⁻¹.

^dConditions: 10 mM Tris, 50 mM NaCl, and 1 mM EDTA; DNA concentration was 40 µg/mL.

^eRef 33.

^fThis work.

^gRef 40.