Protonated polynucleotide structures. IX. Disproportionation of poly (G)·poly (C) in acid medium

Thiele, Danielle; Guschlbauer, Wilhelm

doi:10.1002/bip.360100111

Cited by 72 publications

(17 citation statements)

References 14 publications

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“…In Fig.1D are shown the premelting changes obtained when a normal and an acidified solution were heated simultaneously. These spectra resemble the difference spectra obtained for the dissociation of polynucleotide complexes containing C and/or G [34,35]. The same kind of premelting changes, different after acidification from that which they were before, has been observed with DNA's from other sources.…”

Section: Resultssupporting

confidence: 72%

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Influence of DNA Acidification on DNA Premelting and Template Properties

Sarocchi¹,

Dausse

Guschlbauer³

1976

European Journal of Biochemistry

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Acidification of a T7 DNA sample was found to be partly irreversible as ultraviolet difference spectra measured at various sub-melting temperatures were different from those observed for a 'normal' DNA sample. This implies some subtle conformational change which is not reversed by return to neutral pH. In the same conditions, only poly(purine)-poly(pyrimidine) polymers behaved in a different manner, during premelting, according to whether they were previously acidified or not. The properties of acidified and reneutralized T7 DNA were also investigated for Escherichia coli RNA polymerase binding and transcription. An inhibition of RNA synthesis and chain initiation was observed. The results suggest that the binding of the enzyme is affected. RNA synthesized is specific but there is a decrease in the number and in the stability of the RNA-polymerase-DNA complexes.

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Section: Resultssupporting

confidence: 72%

“…poly(pyrimidine) polymers. While the polymer complexes can (and probably do) form triple-stranded structures [34], DNA will not rearrange itself. The reversibility of the polymer spectra upon heating would correspond to the disproportionation of the triple strand.…”

Section: Resultsmentioning

confidence: 99%

Influence of DNA Acidification on DNA Premelting and Template Properties

Sarocchi¹,

Dausse

Guschlbauer³

1976

European Journal of Biochemistry

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“…A triple-stranded polymer complex of stoichiometry 2C: 1G has been reported a t acid pH by Thiele and Guschlbauer. 28 We cannot reject this as a possible RNA conformation, except to observe that C is present in E. coli RNA in considerably smaller amounts than is G. Studies on systems containing short C and G chains indicate that oligomeric complexes of G and C tend to be triple-rather than double~t r a n d e d ?~.~~ We also note from Figure 9 that a G -G -C structure formed at high pH could easily rearrange to give the G.G low-pH structure which we have discussed above. The failure to form the proposed triple-helical structure in medium of lower ionic strength is attributed to high electrostatic repulsion between the phosphate backbones in the triple strand.…”

Section: Interpretation Of Resultsmentioning

confidence: 94%

Metastable secondary structures in ribosomal RNA: A new method for analyzing the titration behavior of rRNA

1973

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SynopsisThe pH titration behavior of E . coli rRNA in the acid range has been analyzed by combining spectrophotometric and potentiometric titration data. The "simplest" model for the system, which considers as possible reactions the protonation of adenine (A), cytosine (C), and guanine (G) residues along with the opening of A-U and G . C base pairs, does not adequately account for the titration properties. It is postulated that extra reactions may occur in addition to those in the "simplest" model, and a new analytical method was developed to deal with this situation. Our approach yields the ultraviolet spectral changes which accompany the extra reactions, from which the nature of these reactions can in principle be deduced. The calculations also give, a t each pH, the extents of the extra reactions as well as the extents of those reactions which comprise the "simplest" model.We infer that in acidic RNA solutions of 0.lM ionic strength there occur at least two extra reactions, each of which involves G residues. We propose that in the pH range 6.0 2 pH 2 3.8 triple-stranded helical sequences, presumably protonated G .C.G, are formed. These regions are replaced at lower pH by acid-stable structures involving G .G and A.A base pairs. In solutions of lower ionic strength (Z = 0.OlM) no triple strands are formed, but G.G and A. A regions seem to develop even a t pH values as high as 6.0. At Z = O.lM, an acid-base titration cycle between pH 7 and 2.8 is not reversible; rRNA shows true hysteresis behavior. We conclude that in ribosomal RNA's, which are generally G-rich, guanine residues may participate in hitherto unpredicted conformations, some of which may be metastable while others are equilibrium structures.

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“…At pH 6.0 poly(C) begins to form a hemiprotonated duplex of parallel strands that is most stable at pH 4.5 (Guschlbauer, 1975;Langridge & Rich, 1963). Protonated triplexes .with a C, C+, G stoichiometry form between poly(C) and poly<G), oligo G, GMP, GTP, and guanosine (Thiele & Guschlbauer, 1971;Howard et al, 1964;Sarocchi et al ., 1970;Ts Huang, 1968). In complexes between poly(C) and 3 1 -GMP the triplex begins to form at pH 6.6 and triplex formation is complete at pH 5.15 (Sarocchi et lli_., 1970).…”

Section: Methodsmentioning

confidence: 99%

Simultaneous peptide and oligonucleotide formation in mixtures of amino acid, nucleoside triphosphate, imidazole, and magnesium ion

Weber¹,

Caroon²,

Warden³

et al. 1977

Biosystems

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Simultaneous peptide and oligonucleotide formation was observed in reaction mixtures of amino acid, nucleoside triphosphate, imidazole, and MgCl2. At 70 degrees C in solutions that were evaporated to dryness the formation of peptide for phe and pro was greatest with CTP relative to ATP, GTP, and UTP. Lysine exhibited a preference for GTP and glycine for UTP. At ambient temperature insolution at pH 7.8, CTP was preferred by glycine, but at pH 8.7 UTP was preferred. The glycine nucleotide phosphoramidates were also detected and characterized in reactions at 40 degrees C. The glycine-reaction preference for CTP at pH 7.8 and UTP at 8.7 suggested that the basicity of the nucleoside triphosphate was involved in increasing the peptide yield. CTP near neutrality is the most basic nucleoside triphosphate and the basic anionic form UTP could facilitate peptide formation at pH 8.7. These data, together with information on the complexing of poly(C) by GTP, led to the experimentally approchable hypothesis that GTP, by forming a basic triplex between the cytosine residues adjacent to the peptidyl adenosine and aminoacyl adenosine at the termini of two proto-tRNAs, would promote peptide bond synthesis between the aminoacyl residue and peptidyl residue.

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Protonated polynucleotide structures. IX. Disproportionation of poly (G)·poly (C) in acid medium

Cited by 72 publications

References 14 publications

Influence of DNA Acidification on DNA Premelting and Template Properties

Influence of DNA Acidification on DNA Premelting and Template Properties

Metastable secondary structures in ribosomal RNA: A new method for analyzing the titration behavior of rRNA

Simultaneous peptide and oligonucleotide formation in mixtures of amino acid, nucleoside triphosphate, imidazole, and magnesium ion

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