8-Aza-3-deazaguanine modification strengthens the anomeric effect and affects other conformational preferences of modified guanine nucleosides

Plevnik, Miha; Črnugelj, Martin; Štimac, Anton; Kobe, J.; Plavec, Janez

doi:10.1039/b009401n

Cited by 3 publications

(2 citation statements)

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“… a Phase angles of pseudorotation ( P N and P S ) and maximum puckering amplitudes (Ψ m N and Ψ m S ) obtained with computer program PSEUROT are in degrees, rms errors and Δ J max are in Hz, temperature is in K, and populations of N-type conformers and γ rotamers are in %. b Taken from ref . …”

Section: Resultsmentioning

confidence: 99%

“…All proton resonances of sugar and nucleobase protons were completely assigned with the use of 1D 1 H homonuclear decoupling, T 1 relaxation time measurements, and 1D NOE experiments. 3 J HH coupling constants and populations along C4‘−C5‘ bonds for 6 in DMSO- d 6 and data for 4 and 6 in D 2 O were taken from our previous work. Tetramethylsilane (TMS) in DMSO- d 6 and sodium trimethylsilyl propionate (TMSP) were used as internal reference (δ = 0.000 ppm) for 1 H NMR spectra.…”

Section: Methodsmentioning

confidence: 99%

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Conformational Properties of Shape Modified Nucleosides − Fleximers

2004

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A detailed (1)H NMR conformational study complemented with ab initio computations was performed in solution on fleximer nucleosides 1, 3, and 5 in relation to their natural counterparts. The substitution of the purine nucleobase found in the natural nucleosides with a more flexible two-ring heterocyclic system strongly increased the population of anti conformation around the glycosidic bond. This was accompanied by a large shift toward a north-type sugar conformation, which was explained by the interplay of anomeric, gauche, and steric effects. The formal separation of the bicyclic purine base into its imidazole and pyrimidine moieties allows for formation of a hydrogen bond between the NH(2) and 2'-OH groups and facilitates favorable conjugation between the two heterocyclic rings. Our results show that the interplay of stereoelectronic effects, combined with the flexibility of the nucleobase and possible conjugation effects within the nucleobase, plays a crucial role in the search for shape-mimic nucleosides that will interact with flexible binding sites.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%