Adenosine temperature dependence

The temperature dependence of the chemical shifts of the base resonances in poly(dA-dT) and poly(dA-5brdU) are plotted in Figure 5. These data demonstrate that the adenosine H-8 and H-2 protons exhibit very similar behavior over the entire temperature range and are not perturbed by the substitution on the pyrimidine 5 position. 

Figure 5. The temperature dependence of the adenosine H-2, pyrimidine H-6, and adenosine H-8 protons in polyfdA-dT) in 0.1 M phosphate, ImM EDTA, 2H10, pH 7, and poly(dA-5brdU) in 0.1 M NaCl, lOmM phosphate, ImM EDTA, zHiO, pH 8.1...

Figure 11. A comparison of the temperature dependence of the linewidth of the nonexchangeable adenosine H-8 resonance (O) and the exchangeable thymidine H-3 resonance (9) in 1M (-H, C),NCI, 10/nM phosphate, ImM EDTA, aqueous...

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. 

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...

Figure 27. The temperature dependence of the adenosine H-2 resonance (7.1 to 8.1 ppm) for poly(dA-dT) ( ) and the daunomycin poly(dA-dT) complexes, Nuc/D = 50 (A), 25 (O), 9 ( ), and 5 (A.) in IM NaCl, lOrnM cacodylate, 7mM EDTA, HjO solution. The poly(dA-dT) concentration was fixed at I9.3mM in phosphates and the daunomycin concentration was varied to make the different...

Figure 14.42 (page 281) shows the temperature-dependent H spectrum of a 1 1 mixture of adenosine and Poly U. At 30°C, the spectrum is identical to that... 

Rimon, G., Hanski, E., and Levitzki, A., Temperature dependence of j3 receptor, adenosine receptor, and sodium fluoride stimulated adenylate cyclase from turkey erythrocytes. Biochemistry 19, 4451 (1980). 

Figure 8.6.11 Temperature-dependent plot of the shift of N3-labeled adenosine in the DNA duplex d(CGCAATTCGCG)2 after addition of distamycin and netropsin. (A) Average N3 shifts in absence of drug (°) A6N3 shift in netropsin complex shows no effect, except for exclusion of water ( ) A6N3 shift in distamycin complex—shows large effect (E,A) A18N3 shifts are the same in distamycin and netropsin complexes. These results led to hydrogen bonds sketched bold in Figure 8.6.10. (From Rhee et al., 1993.)...

A conformational study of nucleic acid phosphate esters has been carried out using n.m.r. and the temperature-dependent chemical shifts used to give information about the geometry of the phosphodiester linkage. Compounds studied were 3 - and 5-O-methyl phosphates of uridine and adenosine, and the 3-0-methyl phosphate of 6-A-dimethyladenosine. It has been reported that the n.m.r. of myo-inositol hexakisphosphate has four resonances that shift and broaden as a function of pH. ° Reference to the use of P n.m.r. in the configurational determination of cyanomethyl-branched phosphonates is made in Chapter 16. 

E.L. Kovrigin, R, Cole, J.P. Loria, Temperature dependence of the backbone dynamics of ribonuclease A in the ground state and bound to the inhibitor 5 -phosphothymidine (3 -5 )pyrophosphate adenosine 3 -phosphate, Biochemistry 42 (2003) 5279-5291. 

Retter [82] has shown that from the temperature dependence of the pit width the surface concentration of the adsorbed molecules can be calculated. For the potential region of the cathodic capacitance pit of 9 mM adenosine in 0.5 M KCl with a Me Ilvaine buffer, pH 7, it was found that rj = 3.1 x 10" mol cm"-. This surface concentraion corresponds to an area of 0.55 nm- occupied by one molecule, i.e., to the perpendicularly adsorbed adenosine molecules. 

Fig. 2. The dependence of nucleoside-protein conjugation on pH. A mixture of periodate-oxidized adenosine and cytidine was added to bovine y-globulin to give final concentrations of 4 mM nucleoside (0.9 mg/ml) and 6.7 ftM protein (1 mg/ml) in 0.2 M Veronal buffer titrated to varying pH. These mixtures were incubated at room temperature for 1.5 hr. Then sodium borohydride was added to a final concentration of 0.4 M (15 mg/ml), and samples were incubated for 2.5 hr at 4°. They were then dialyzed extensively against 0.1 M NaCl and analyzed for protein and nucleoside composition.

The complicated solubility relations, rates of hydrolysis, sclf-disproportionation and intcrcon-version with other phosphates depends sensitively on pH, conccniralion, temperature and the presence of impurities." Though of great interest academically and of paramount importance industrially thc.sc aspects will not he further considered here. " " Triphosphates such as adenosine triphosphate (ATP) arc also of vital importance in living organisms (.sec text books on biochemistry, and also ref. 141). 

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