Tautomerism of nucleic acid bases.  Erratum

Pieber, M.; Kroon, Paul A.; Prestegard, J.H.; Chan, Sunney I.

doi:10.1021/ja00791a069

Cited by 18 publications

(6 citation statements)

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“…bonds, the chemical structure of the methoxylated adenine base must be the imino form, as shown in Figure 6, since it is known that the cytosine base exists only in the amino form (Pieber et al, 1973). This is consistent with the structures found in N 6methoxyadenine derivatives (Birnbaum et al, 1984;Fujii et al, 1990), which take the imino form.…”

Section: Tautomerism Of Mo 6 a And Hydrogenbonding Schemesupporting

confidence: 76%

Crystallographic studies on damaged DNAs. I. an N6-methoxyadenine residue forms a watson-crick pair with a cytosine residue in a B-DNA duplex

Chatake

Ono

Ueno

et al. 1999

Journal of Molecular Biology

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Section: Tautomerism Of Mo 6 a And Hydrogenbonding Schemesupporting

confidence: 76%

Crystallographic studies on damaged DNAs. I. an N6-methoxyadenine residue forms a watson-crick pair with a cytosine residue in a B-DNA duplex

Chatake

Ono

Ueno

et al. 1999

Journal of Molecular Biology

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“…The relaxation amplitude was found to be pH independent in the pH range [6][7][8][9] and proportional to the cytosine concentration. It varies with the wavelength of the analyzing light with a maximum at 297 nm [Figure 1 (a)].…”

Section: Resultsmentioning

confidence: 93%

“…In contrast, the nontautomeric compound Vb showed no relaxation spectrum other than the "fast" relaxation effect X I0~J M (lower curve); t; = 4 °C; if = I0°C; X = 254 nm. (Lower) Relaxation spectrum of 3-mcthylcytosine in heavy water, recorded for a wavelength of 254 nm: t\ = 4 °C; If = 10 ± 1 °C; pD (as measured at ?i) 9.70; 3-mcthylcytosinc concentration = 2.07 X I0~3 M; vertical scale, 2 X 10~3 OD unit per major division; horizontal scale, 20 us per major division. The signal corresponds to an increase of the solution OD.…”

Section: Relaxation Spectrum Of 3-methylcytosine and Relatedmentioning

confidence: 99%

Tautomerism in cytosine and 3-methylcytosine. A thermodynamic and kinetic study

Dreyfus¹,

Bensaude²,

Dodin³

et al. 1976

J. Am. Chem. Soc.

145

112

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Aqueous cytosine, which exists mainly as the 1 (//)-aminooxo form (la), is shown by temperature-jump spectroscopy to tautomerize slightly to the 3(//)-aminooxo form (Ila); the equilibrium constant K = (IIa)/(Ia) is estimated to be (2.5 ± 0.5) X 10-3 at 25 °C and the tautomerization enthalpy is 3.1 ± 0.1 kcal M_1. At 10 °C, The interconversion process is catalyzed by water [kH2o = (1.8 ± 0.3) X 103 s~1 ], by H+ [kH+ = (1.6 ± 0.3) X 1010M-' s-'],by OH" [fc0H-= (1.2 ±0.05) X 1010 M_1 s_1], and by the cytosinium cation [kcat;on = (4.4 ± 0.2) X 108 M_l s-1]. On the other hand, 3-methylcytosine is shown by uv and ir spectroscopy to exist as a mixture of two tautomeric forms, the aminooxo form lib and the iminooxo form Illb; while Illb is the major form in nonpolar solvents, the amino form lib largely predominates in water, the equilibrium constant K' = (Illb)/(lib) being estimated as ca. 3 X 10-2 at 25 °C. The Ilb^Illb interconversion mechanism was investigated in D20 solution at 10 °C by temperature-jump spectroscopy. The interconversion is catalyzed by D20 [ko2o = (2.9 ± 0.3) X 104 s~'], by OD~[ £od-= (4.3 ± 0.2) X 109 M_1 s-1], and by cationic 3-methylcytosine [kCation = (2.2 ± 0.1) X 108 M_l

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“…This holds for a variety of solvents with different dielectric constants and even in the vapor state (435). Earlier NMR investigations on cytosine and guanine derivatives which traced about 15% of the rare imino and enol forms later proved erroneous (436,437). Quantum chemical calculations are not adequate to furnish details on tautomeric states because they are too sensitive to uncertain O-H bond lengths (438).…”

Section: Tautomerism Of Basesmentioning

confidence: 99%

“…We should also recall here the back-and-forth folding of DNA in the rod-like particles of about 2000 A length (Section 19.1), which indicates that 2000 A or -60 turns of B-DNA with 34 A pitch appear to be a magic number of DNA self-assembly. 436 19: Higher Organization of DNA IfL Figure 19·2. Electron micrograph of crystals obtained from about 2000.A-Iong fragments of salmon sperm DNA.…”

Section: Lamellar Microcrystals Formed By Fragmented Dnamentioning

confidence: 99%