Netropsin poly

Figure 33. The 360-MHz correlation proton NMR spectra of the netropsin poly(dA-dT) complex in 0.1 M NaCl, lOmM cacodvlate, lOmM EDTA, 80% HtO-20% 2Ht0. Spectrum A corresponds to the Nuc/D = 25.5 complex, pH 6.1 at 47°C while Spectrum B corresponds to the Nuc/D = 12.8 complex, pH 6.15...

Lower Temperature Cooperative Transition The NMR parameters for the dissociation of the Nuc/D = 50 netropsin poly(dA-dT) complex have been carefully investigated in 0.1 M phosphate solution, conditions under which 1 netropsin is bound for every 25 base pairs. The nonexchangeable proton NMR spectra (5 to 9 ppm) of the lower temperature cooperative transition between 53.2°C and 68.5°C are presented in Figure 35. 

Biphasic Duplex to Strand Transition Midpoints (t, °C) monitored at the 260 nm Absorbance of Netropsin Poly(dA-dT) Complexes in Solution3... 

Figure 36. The temperature dependence (40° to 100°C) of the sugar H-l chemical shifts of poly(dA-dT) (O) and the netropsin poly(dA-dT) complex, Nuc/D = 50 (9) in 01M cacodylate, 4.4mM EDTA, 2HlO solution...

Netropsin Migration Along Partially Opened DNA The plots of the sugar H-l chemical shifts in the Nuc/D = 50 netropsin poly(dA-dT) complex in 0.1 M buffer demonstrate that the lower temperature and higher temperature cooperative transitions exhibit midpoints of 61°C and 95°C, respectively (Figure 36). This section covers the NMR spectral parameters for the complex between these temperature values (65 and 90°C) with typical spectra in the 5 to 9 ppm presented in Figure 38. 

Figure 39. The temperature dependence of the chemical shifts and linewidths of the base resonances of poIy(dA-dT) (O) and the Nuc/D = 50 netropsin poly-(dA-dT) complex ( J in 0.1 M cacodylate, 4.4mWl EDTA, 2HiO, pH 7.25...

Antibiotic Resonances The protons on the N-methylpyrrole rings of netropsin can be detected in the 1 antibiotic per 5 base pair netropsin poly(dA-dT) complex at 87°C (Figure 41). The proton line widths indicate that the entire complex is intact at this... 

Figure 41. The 360-MHz proton NMR spectrum (4.5 to 9.0 ppm) of the Nuc/D = 10 netropsin poly(dA-dT) complex in 0.1 M cacodylate, 4.4mM EDTA 2H 0, pH 7.08 at 87°C. The tentatively assigned N-methylpyrrole protons of netropsin are...

The experimental complexation shift represents the difference between the Nuc/D = 10 netropsin poly(dA-dT) complex at 87.0°C and the dissociated compoents at 96.8°C. 

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