213. Deoxypentose nucleic acids. Part II. Electrometric titration of the acidic and the basic groups of the deoxypentose nucleic acid of calf thymus

Gulland, John Masson; Jordan, D. O.; Taylor, H. F. W.

doi:10.1039/jr9470001131

Cited by 85 publications

(22 citation statements)

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“…A particular case is the titration of DNA at 25°C with either acid or alkali, which leads to denaturation at the extremes of pH, and the denatured form persists for a long period when the solution is neutralized. The pH-titration curve followed before denaturation is distinct from that followed after denaturation, and the original curve is never retraced (Gulland et al, 1947;. Vol.…”

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confidence: 98%

Hysteresis and conformational changes in ribosomal ribonucleic acid

Cox¹,

Katchalsky

1972

Biochemical Journal

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Both rat liver and Escherichia coli rRNA in 0.1m-sodium chloride were titrated with acid or alkali over the range pH3-7 at approx. 0 degrees C. rRNA did not bind acid reversibly and hysteresis was observed, i.e. the plot of acid bound to rRNA against pH had the form of a loop showing that the amount of acid bound at a particular pH depended on the direction of the titration. Although the boundary curves were reproducibly followed on titration from pH7 to 3 and from pH3 to 7, points within the loop were ;scanned', e.g. by titration from pH7 to a point in the range pH3-4 followed by titration with alkali to pH7. It is inferred that the ;lag' in the release of certain bound protons is at least 1 pH unit, that at least about 9-15% of the titratable groups (adenine and cytosine residues) that are involved in this process and that the free energy dissipated in completing a cycle is approx. 4.2kJ/mol (1kcal/mol) of nucleotide involved in hysteresis. The interpretation of the ;scanning' curves was illustrated by means of a cycle of possible changes in the conformation of a hypothetical nucleotide sequence that allows formation of poly(A).poly(AalphaH(+))-like regions in acidic solutions. It is also inferred that the extent of ;hysteresis' might depend on the primary nucleotide sequence of rRNA as well as on secondary structure.

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confidence: 98%

Hysteresis and conformational changes in ribosomal ribonucleic acid

Cox¹,

Katchalsky

1972

Biochemical Journal

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“…The main method applied at the time to investigate the macromolecular structure of DNA in solution (as opposed to X-ray diffraction studies of the fibres) was electrometric titration, in the hands of J. M. Gulland, D. 0. Jordan and their team at Nottingham (13). They had been able to establish the important feature that the native conformation of DNA was disrupted by titration of either its basic or acidic groups.…”

Section: The Advent Of Dna As a Biological Targetmentioning

confidence: 99%

Alkylation of DNA and its aftermath

Lawley

1995

BioEssays

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Current pharmacopoeias invariably refer to a category of 'alkylating drugs', still among the most widely used in cancer chemotherapy. They are described as acting through their ability to damage DNA, thus interfering with cell replication. Unfortunately, this mode of action implicates these drugs as carcinogens. Thus the early studies recalled in this essay proved to be relevant to our understanding of both the main problems with which cancer research concerns itself: the causation of cancer and possible methods of treatment of this group of diseases.

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“…The pK values reported for primary phosphate in nucleotides and nucleic acids (43,44) are less than I. Thus, when the primary phosphate groups are half undissociated, the DNA is completely inactive (Fig.…”

Section: H + and Oh-ions-mentioning

confidence: 99%

“…The irreversible changes in the molecule must therefore be held responsible for inactivation. As mentioned in connection with heat, it has been recently suggested (22,26,27) that the decrease of viscosity upon mild H + treatment may be due to an irreversible change in association (38) or to the change of asymmetry of the molecule when the molecule contracts; this may be due to the breakage of very few labile bonds, such as hydrogen bonds (44)(45)(46)(47)(48)(49) or bonds between the phosphate and the first carbon of the sugar (50). The inactivation of the transforming principle may indeed be due to the irreversible breaking of these bonds.…”

Section: H + and Oh-ions-mentioning

confidence: 99%

Studies on the Chemistry of the Transforming Activity

Zamenhof

Alexander

Leidy

1953

Journal of Experimental Medicine

144

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Avery, MacLeod, and McCarty (5) found that the purified transforming principle of Streptococcus pneumoniae has the properties of a highly polymerized desoxypentose nucleic acid (DNA). This conclusion was based mainly on two facts: (a) the active preparation consisted of highly polymerized DNA, and substances other than DNA could not readily be detected in it, and (b) of many enzymes tested, only desoxyribonuclease (DNase), in minute quantities, could destroy the transforming activity. These results were corroborated by McCarty and Avery (6, 7), and by Hotchkiss (8); in particular, Hotchkiss obtained evidence that the purified and active transforming principle may contain no more than 0.02 per cent protein and that the progressive purification of DNA does not result in any significant decrease of the transforming activity.Similar evidence was obtained when studying the transforming principles of other bacterial species, ttemophilus influemae (9, 10) and Neisseria meningitidts (ll, 12).The above findings have opened the possibilities for more detailed studies of the chemistry of the transforming activity. Avery, MacLeod, and McCarty (5) studied qualitatively the resistance of the transforming activity to various agents; the resistance was much higher in the non-purified than in the purified transforming principle. McCarty (13) studied the inactivation of the transforming principle by ascorbic acid and other serf-oxidizing agents, and the reactivation by reducing agents. However, to the authors' knowledge, no other study on the chemistry of the transforming activity has been reported.The object of the present work is such a study. The purpose of this study is manifold. The first aim is to obtain still more evidence as to the DNA nature of the transforming principle. Another object is to determine safe conditions

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213. Deoxypentose nucleic acids. Part II. Electrometric titration of the acidic and the basic groups of the deoxypentose nucleic acid of calf thymus

Cited by 85 publications

References 0 publications

Hysteresis and conformational changes in ribosomal ribonucleic acid

Hysteresis and conformational changes in ribosomal ribonucleic acid

Alkylation of DNA and its aftermath

Studies on the Chemistry of the Transforming Activity

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