Sequences and photophysical properties of tag RNA strands and ECHO probes. ^a

aECHO probes consisted of 2′-O-methyl ribonucleotides except for D514 and D640 2′-deoxyribonucleotide. bAll Tm values of the tag–probe hybrids (500 nM) were obtained in a HEPES buffer (120 mM KCl, 5 mM NaCl, 25 mM HEPES, pH = 7.2). cFluorescence quantum yield measured using 100 nM probe in the HEPES buffer on excitation at 480 nm for anti-gau-D514 and anti-aga-D514 and at 600 nm for anti-ggc-D640. dRatio of the fluorescence intensities of the tag–probe hybrids and probe alone at the λem of hybrids.