Strong impact of chloro substituent on TOTO and YOYO ds-DNA/RNA sensing

Polycationic Monomeric and Homodimeric Asymmetric Monomethine Cyanine Dyes with Hydroxypropyl Functionality—Strong Affinity Nucleic Acids Binders

“…Prior to the NMR experiments the samples were dissolved in a deuterated DMSO. The characterization of the TO derivatives was conducted on a DRX 400 Avance Bruker NMR spectrometer (Bruker Biospin GmbH, Rheinstetten, Germany) operating at the 1 H frequency of 400.31 MHz and a 13 C frequency of 100.66 MHz using a commercial Bruker 5 mm BBO dual channel probe head equipped with z-gradients. A Eurotherm 847 temperature controller with a ± 0.1° precision controlled the temperature.…”

“…The 13 C NMR spectra were acquired applying power gated decoupling scheme and 1k scans. 13 C DEPT 135 (distortionless enhancement by polarization transfer) was recorded with 2k scans and 2 s repetition time. 13 C APT (attached proton test) recorded with 10k scans and 2 s recycle delay experiments was used in some cases to help assign the 13 C NMR resonances.…”

“…13 C DEPT 135 (distortionless enhancement by polarization transfer) was recorded with 2k scans and 2 s repetition time. 13 C APT (attached proton test) recorded with 10k scans and 2 s recycle delay experiments was used in some cases to help assign the 13 C NMR resonances. The sequence was optimized on long-range couplings.…”

“…The spectrometer was operated by Topspin 1.3 patchlevel 8 (Bruker Biospin GmbH, Rheinstetten, Germany). The 1 H and 13 C NMR spectra were referenced to external TMS at 0 ppm. All spectra were evaluated using Mestrec.…”

“…Additional methylation of dyes yielded by the absence of kinetic AT selectivity, but also the appearance of the AT selective fluorescence response [12]. Chloro substitution of the oxazole yellow homodimer (YOYO) resulted in a specific fluorimetric response of ds-RNA compared to ds-DNA, while the chlorinated TOTO analogue revealed specific CD recognition of alternating-DNA sequences concerning homo-DNA and homo-RNA sequences [13]. Monomethine cyanine dyes based on thiazolo [4,5-b]pyridinium and quinolinium chromophores revealed higher sensitivity to DNA when compared to commercial dimeric cyanine dye TOTO-1 [14].…”