Experimental studies of thermal denaturation of the Na-DNA system with respect to manning's model

Rix-Montel, M.A.; Grassi, H.; Vasilescu, D.

doi:10.1016/0301-4622(74)80054-2

Cited by 13 publications

(4 citation statements)

References 19 publications

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“…The proper form of to use in this case is 0.5£a_1 + 0.5 _1 -| • _1 (see Record et al (1976) for the case of (A)fl-(U)" -*• (A)" + (U)"). Using linear phosphate spacings of 3.3 Á for (dA)" and 1.65 Á for (dA)"v2d-Tg, and the e2kkT value of 7.1 , a phosphate spacing of 4.9 Á is calculated for single-stranded d-Tg, somewhat higher than the values of 4.4 Á for (rU)" (Record et al, 1976) and 4.7 Á for single-stranded DNA (Rix-Montel et al, 1974) calculated by analogous procedures. It should be emphasized that at the high sodium ion concentrations (0.04 to 1 M) used in our determination of dTm/d log tiNa-s the length of the octamer is much greater than the Debye screening length, so that the use of polyelectrolyte theory is justified.…”

Section: Discussionmentioning

confidence: 85%

Duplex formation of a nonionic oligo(deoxythymidylate) analog [heptadeoxythymidylyl-(3'-5')-deoxythymidine heptaethyl ester (d-[Tp(Et)]₇T)]with poly(deoxyadenylate). Evaluation of the electrostatic interaction

Pless¹,

Ts’o²

1977

Biochemistry

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The heptaethyl ester of heptadeoxythymidylyl-(3'-5')-deoxythymidine (d-[Tp(Et)]7T or d-T8-Et) has been prepared by chemical methods. The material, consisting of a mixture of diastereoisomers, forms a 1:1 complex with (dA)n in neutral aqueous buffer; this interaction is virtually independent of ionic strength. The octamer triester does not bind to (dA)n-(dT)n, and it interacts with (rA)n only at low temperatures. By cochromatography with (dA)n on Sephadex G-50, d-T8-Et fractions with different binding affinities for the polyadenylates were obtained. This heterogeneity in binding affinity is ascribed to the diastereoisomerism of d-T8-Et. Enthalpies of dupoex formation were determined by the concentration variation method. At 0.1 M sodium ion concentration, the enthalpy of binding of the various d-T8-Et fractions to (dA)n is essentially invariant (-8.1 kcal/mol of base pairs at 0 degrees C to -8.6 kcal at 25 degrees C) and 1.6 kcal/mol of base pairs more negative than the enthalpy of binding of the phosphodiester analogue, d-(Tp)7T, to (dA)n (-6.8 kcal/mol of base pairs at 11 degrees C). This difference is the electrostatic contribution to the enthalpy of duplex formation, arising from the interstrand electrostatic repulsion and the intrastrand repulsion in d-(Tp)7T. The entropy of binding to (dA)n is more negative for the octamer triesters than for the diester analogue, and is different for the various d-T8-Et fractions. This is interpreted in terms of varying degrees of restriction of rotational freedom for the ethyl substituents upon double helix formation.

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Section: Discussionmentioning

confidence: 85%

Duplex formation of a nonionic oligo(deoxythymidylate) analog [heptadeoxythymidylyl-(3'-5')-deoxythymidine heptaethyl ester (d-[Tp(Et)]₇T)]with poly(deoxyadenylate). Evaluation of the electrostatic interaction

Pless¹,

Ts’o²

1977

Biochemistry

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“…Since b c > b h for transitions from double or triple helix to single strands, therefore gjT 1 -gj" 1 > o and AM M + > o; counterions are released in the denaturation reaction. Counterion release has been detected electrochemically by Rix-Montel, Grassi & Vasilescu (1974) in the denaturation of DNA. The relationship between K O ba and K% for helix-coil equilibria is (cf.…”

Section: Transitionsmentioning

confidence: 99%

Thermodynamic analysis of ion effects on the binding and conformational equilibria of proteins and nucleic acids: the roles of ion association or release, screening, and ion effects on water activity

1978

Quart. Rev. Biophys.

1,653

1,047

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The purpose of this review is to examine the various effects of low- molecular-weight electrolytes on the associations and interactions of proteins and nucleic acids. Our primary interest is in general electrostatic effects, rather than chemical effects (specific interactions) of particular ions (e.g. transition metals, protons). We consider those interactions in which a variation in salt concentration has a significant effect on the macromolecular equilibrium, and analyse the effects of salt in these situations in terms of (i) direct participation of ions in the biopolymer reaction, (ii) Debye—Hückel screening by salt ions of the charge interactions on the biopolymers, and (iii) the reduction in water activity brought about at high salt concentrations.

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“…The former seems more probable from known structures of agarose and carrageenans. A more precise measure of b for XCPS may be obtainable from measurements of counterion activity in a titration experiment (Rix-Montel et al, 1974).…”

Section: 4mentioning

confidence: 99%

Conformation of the extracellular polysaccharide of Xanthomonas campestris

Holzwarth¹

1976

Biochemistry

189

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The solution conformation of the extracellular polysaccharide of the bacterium Xanthomonas campestris is examined by optical rotation, viscometry, and potentiometric titration. Measurements of optical rotation vs. temperature for solutions of the polysaccharide at low ionic strength reveal a sharp transition to a denatured structure which is reversible if sufficient salt is present. The temperature Tm at the transition midpoint increases as log (Na+) or log (Ca2+). Viscosity-temperature profiles substantiate a structural change of the polysaccharide at Tm. The intrinsic viscosity of the native molecule at zero shear rate exceeds 5000 ml/g. This high figure is indicative of a stiff chain. The viscosity of the native molecule is relatively insensitive to salt, whereas the denatured molecule collapses if salt is present. Hydrogen-ion titration shows that the pKapp of the COO- groups of the polymer decreases from 3.2 in 0.01 M NaC1 to 2.6 in 0.2 M NaC1. All these data suggest that the native polysaccharide possesses ordered secondary structure stabilized by nonionic interactions outweighing the repulsion between adjacent COO- groups.

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Experimental studies of thermal denaturation of the Na-DNA system with respect to manning's model

Cited by 13 publications

References 19 publications

Duplex formation of a nonionic oligo(deoxythymidylate) analog [heptadeoxythymidylyl-(3'-5')-deoxythymidine heptaethyl ester (d-[Tp(Et)]₇T)]with poly(deoxyadenylate). Evaluation of the electrostatic interaction

Duplex formation of a nonionic oligo(deoxythymidylate) analog [heptadeoxythymidylyl-(3'-5')-deoxythymidine heptaethyl ester (d-[Tp(Et)]₇T)]with poly(deoxyadenylate). Evaluation of the electrostatic interaction

Thermodynamic analysis of ion effects on the binding and conformational equilibria of proteins and nucleic acids: the roles of ion association or release, screening, and ion effects on water activity

Conformation of the extracellular polysaccharide of Xanthomonas campestris

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Experimental studies of thermal denaturation of the Na-DNA system with respect to manning's model

Cited by 13 publications

References 19 publications

Duplex formation of a nonionic oligo(deoxythymidylate) analog [heptadeoxythymidylyl-(3'-5')-deoxythymidine heptaethyl ester (d-[Tp(Et)]7T)]with poly(deoxyadenylate). Evaluation of the electrostatic interaction

Duplex formation of a nonionic oligo(deoxythymidylate) analog [heptadeoxythymidylyl-(3'-5')-deoxythymidine heptaethyl ester (d-[Tp(Et)]7T)]with poly(deoxyadenylate). Evaluation of the electrostatic interaction

Thermodynamic analysis of ion effects on the binding and conformational equilibria of proteins and nucleic acids: the roles of ion association or release, screening, and ion effects on water activity

Conformation of the extracellular polysaccharide of Xanthomonas campestris

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Duplex formation of a nonionic oligo(deoxythymidylate) analog [heptadeoxythymidylyl-(3'-5')-deoxythymidine heptaethyl ester (d-[Tp(Et)]₇T)]with poly(deoxyadenylate). Evaluation of the electrostatic interaction

Duplex formation of a nonionic oligo(deoxythymidylate) analog [heptadeoxythymidylyl-(3'-5')-deoxythymidine heptaethyl ester (d-[Tp(Et)]₇T)]with poly(deoxyadenylate). Evaluation of the electrostatic interaction