Thymidine chemical shift

The similarity in the pyrimidine carbon resonances in cytidine and deoxycytidine is indicative of the independence of these shifts from the sugar fragments. The differences observed between the chemical shifts of uracil and thymine, or uridine and thymidine, indicate that they must result from the presence of the 5-methyl group in the latter. The downfield shifts ( — 7.5 ppm) of the 05 peaks of uracil or uridine upon 5-methyl substitution are typical for a carbon directly substituted by a... 

Fig. 5.10. Plot of 13C chemical shifts versus rc-charge densities [749], calculated by Fcrnan-dez-Alonso [765]. (Adenosine O, guanosine n, inosine A, xanthosine O, uridine . cyti-dine , thymidine .)...

The configurations of the cyclic thymidine 3, 5 -[170, 180]-monophosphates can be conveniently assigned by 170 NMR spectroscopy. We have previously reported that in aqueous solution at 95° C the 170 NMR chemical shifts of the phosphoryl oxygens of cyclic 2 -deoxyadenosine 3, 5 -[170, 180]monophosphate are sufficiently different at 36.6 MHz such that two resonances can be resolved in a racemic mixture of the diastereomers, with the down-... 

H2O solution (6 to 14 ppm) were recorded between 0° and 55°C and the exchangeable protons identified by comparison with the corresponding spectra recorded in 20 solution. The thymidine H-3 imino hydrogen-bonded resonance is observed at 13.0 ppm in the spectrum of poly(dA-dT) at 25.5°C (Figure 1A) and its chemical shift and line width dependence are plotted as a function of temperature in Figures IB and 1C respectively. 

NMR spectrum of the thymidine H-3 proton in polv(dA-dT) in 0.1 M phosphate, ImM EDTA, H,0 at 25.5°C. The (B) chemical shifts and (C) iinewidths of this proton in the synthetic DNA in 0.1 M phosphate are plotted as a function of temperature between 0° and 55°C. The poly(dA-dT) duplex exhibits a duplex-to-strand transition midpoint of 59°C. 

The chemical shifts are similar at high temperature and differ by uO.l ppm at the lower temperature (Figure 12). This suggests that similar base pair overlaps are observed for poly(dA-dT) in 1 M Na+ and 1 M TMA+ as monitored at the thymidine H-3 proton located in the center of the base pair. 

Figure 12. A comparison of the tern- g perature dependence of the thymidine H-3 proton chemical shift of poly(dA-dT) in 1M NaCl, lOmM cacodylate, O.lmM EDTA, H.O, pH 6.53 (9) and in /M (2H, C),NCl, lOmM phosphate, ImM EDTA, HiO, pH 7.5(0)...

The dissociation of the proflavine poly(dA-dT) complex can be followed by monitoring the temperature dependent chemical shift or the line width as demonstrated by shift data on the thymidine CH3-5 resonance (Figure 18A) and width data on the adenosine H-8 resonance (Figure 18B). The proton resonances shift as average peaks during the dissociation of the complex, indicative of fast exchange ( dissociation 10 sec l at the transition midpoint) between the complex and its dissociated components on the NMR time scale. 

Nucleic Acid Base Resonances The chemical shifts of the nonexchangeable protons in poly(dA-dT), the Nuc/D = 24 complex and the Nuc/D = 8 complex in 1 M NaCl solution are plotted as a function of temperature in Figure 19. The nucleic acid nonexchangeable proton chemical shifts in the duplex state are either unperturbed (adenosine H-8, H-2, and thymidine CH3-5) or shift slightly upfield (thymidine H-6) on complex formation (Figure 19). By contrast, the thymidine H-3 exchangeable proton located in the center of the duplex resonates 0.35 ppm to higher field in the Nuc/D = 8 proflavine complex compared to its position in the... 

Figure 18. The temperature dependence of (A) the thymidine CH.,-5 chemical shift and (B) the adenosine H-8 linewidth in poly(dA-dT) (O), the proflavine polv(dA-dT) complex, Nuc/D 24 (A) and Nuc/D = 8(9) in 1M NaCl, lOmM cacodylate, lOmM EDTA, sH.O, pH 7...

Chemical Shift of the Thymidine H-3 Proton In Poly(dA-dT) and Its Daunomycin Complex rnlMNaCl Solution... 

Figure 37. The variation of the sugar H-l and base proton (adenosine II-8, H-2, and thymidine CH t-5) chemical shifts of 24mM poty(dA-dT) in 0.1 M cacodyiate, lOmM EDTA, 2HiO, pH 7.25, 53°C on gradual addition of netropsin...

Wang JF et al (1992) Solution studies of staphylococcal nuclease H124L. 2. IH, 13C, and 15N chemical shift assignments for the unligated enzyme and analysis of chemical shift changes that accompany formation of the nuclease-thymidine 3, 5 -bisphosphate-calcium ternary complex. Biochemistry 31(3) 921-936... 

The value of — 22.6 0.6 kj mor obtained is similar to that of other hemi-acetal phosphoric esters. Treatment of 4-( -acetyl-2,3-< -carbonyl-a-L-rhamno-pyranosyl bromide with dibenzyl phosphate-triethylamine, followed by deprotection, yielded j3-L-rhamnopyranosyl phosphate. The same paper contains a synthesis of thymidine 5 H/ L fhamnopyranosyl)pyrophosphatc. Long-chain (C10-C16) alkyl 0-D-glucopyranosyl phosphates have been prepared via the orthoester method and described as novel anionic detergents. The MacDonald procedure (anhydrous phosphoric acid in vacuo at 56-60 for 2 h) has been used to convert di- and tri-saccharides into their a-glycosyl phosphates. The syntheses and n.m.r. of 2-acetamido-2-deoxy-D-glucose 1-, 3-, 4-, and 6-phosphates have been published. The chemical shifts were studied with respect to the position of the phosphate group D-Ribofuranosyl ribitol... 

Table 1. Chemical shifts b (In ppm from internal (trimethylsilyl) propionate) and A6 values of the base protons in uridine, thymidine, and adenosine derivatives. Sas le concentrations in D O,...

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