The C conformation is a low salt form of sodium DNA

Rhodes, N.J.; Mahendrasingam, A.; Pigram, W. J.; Fuller, W.; Brahms, J.; Vergne, Jacques; Warren, R. A. J.

doi:10.1038/296267a0

Cited by 33 publications

(22 citation statements)

References 14 publications

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“…Commercially purchased E.coli DNA was purified using previously described techniques (21) and the ionic content controlled so that fibres could be drawn which at 75% relative humidity reproducibly assumed the A conformation. Diffraction data were recorded using the single crystal diffractometer D 19 at the Institut LaueLangevin, Grenoble, with a wavelength of2.42A (19).…”

Section: Methodsmentioning

confidence: 99%

A High Angle Neutron Fibre Diffraction Study of the Hydration of the A Conformation of the DNA Double Helix

Langan

Forsyth

Mahendrasingam

et al. 1992

Journal of Biomolecular Structure and Dynamics

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A high angle neutron fibre diffraction study of the distribution of water around the A-form of DNA has been performed using the diffractometer D19 at the Institut Laue-Langevin, Grenoble. These experiments have exploited the ability to replace H2O surrounding the DNA by D2O so that isotopic difference Fourier maps can be computed in which peaks are identified with the distribution of water in the unit cell. All peaks of significant height have been accounted for by four families of water molecules whose positions and occupancies have been determined using least squares refinement. The coordinates of the water peaks making up each family do not deviate significantly from a regular helical arrangement with the same parameters as the DNA. Two of these families are of particular interest. The first consists of water molecules in the major groove linking successive charged phosphate oxygens along the polynucleotide chains. The second is associated with bases in the major groove and forms a central core of density along the helix axis. These two families provide a layer of hydration lining the interior wall of the major groove leaving a central channel to accommodate cations. The relationship between these observations and conformational stability is discussed.

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Section: Methodsmentioning

confidence: 99%

A High Angle Neutron Fibre Diffraction Study of the Hydration of the A Conformation of the DNA Double Helix

Langan

Forsyth

Mahendrasingam

et al. 1992

Journal of Biomolecular Structure and Dynamics

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“…Again, this behavior is in agreement with the theory presented here which predicts that the A form is electrostatically more favorable than B above 1.8 M NaCl. The C conformation has been originally described as a low humidity form ofDNA in fibers containing Li + ( 45) but more recent work (60) provides evidence that it may be routinely observed in Na+ containing fibers as well. On the basis of CD spectra, it had been earlier suggested (61)(62)(63) that DNA in concentrated salt solutions converts to conformations of the C family but more recent X-ray diffraction studies of fibers immersed in such solutions ( 64) do not provide evidence that such conversions occur.…”

Section: Stabilities Of Right-handed Helicesmentioning

confidence: 96%

Relative Stabilities and Transitions of DNA Conformations in 1:1 Electrolytes: A Theoretical Study

Soumpasis

Wiechen

Jovin

1987

Journal of Biomolecular Structure and Dynamics

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We use a recently developed formalism (1) to calculate the salt dependent part of the free energy determining DNA conformational stability in 1:1 electrolytes. The conformations studied are the A, B, C and alternating-B right-handed forms and the ZI, ZII left-handed forms of DNA. In the case of the B-ZI transition of d(G-C).d(G-C) helices in NaCl solution, the free energy contribution considered suffices to describe the transition in a quantitative manner. The theory also predicts the occurrence of salt-induced B-A transitions which have been recently observed with poly[d(n2 A-T)] and poly[d(G-C)]. In other cases, additional terms in the free energy balance, particularly due to hydration effects, must be at least as important as salt effects in determining conformational stability and structural transitions in solution. If diffuse ionic cloud electrostatic effects alone would dominate in all cases, the relative helical stabilities at 0.2 M monovalent salt would decrease in the order C greater than B greater than A greater than ZII greater than ZI greater than alternating-B. At high salt concentrations (2.0 M-5.0 M), the order would be alternating-B greater than ZI greater than A greater than ZII greater than B greater than C.

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“…The B-A transition can be inhibited by insufficient milieu conditions, e.g., type of cations, salt concentration etc. (2)(3)(4) or by the interaction of DNA with ligands (5-8a). Then, the DNA exists at medium RH values in a less-defined dehydrated form within the B family designated as C-DNA (3).…”

Section: Introductionmentioning

confidence: 99%

Infrared linear dichroism of oriented DNA-ligand complexes prepared with the wet-spinning method

Fritzsche¹,

Rupprecht

Richter³

1984

Nucl Acids Res

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Oriented DNA films prepared by the wet-spinning technique have been complexed with several ligands: the anthracycline antibiotic violamycin BI, the dipeptide L-carnosine, and the oligopeptide antibiotic netropsin. The formation of the DNA-ligand complexes is accompanied by dramatic changes of the conformational flexibility of DNA. The B-A transition which occurs usually between 80% and 70% relative humidity (RH) is more or less suppressed by the ligands. Violamycin BI at a total ligand per DNA base pair ratio, r , of '0.03 and L-carnosine at rt X' 1.5 inhibit the B-A transition of "'18 and "'0.25 base pairs per ligand molecule, respectively. Netropsin at rt = 0.2 induces a very stable B-DNA even at rather low RH (23 %). The total hydration of this complex is significantly higher than for a drug-free DNA film. Netropsin-DNA complexes at r of 0.02 and 0.01 result in an inhibition of "45 base pairs pe4 drug molecule with respect to the B-A transition.

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The C conformation is a low salt form of sodium DNA

Cited by 33 publications

References 14 publications

A High Angle Neutron Fibre Diffraction Study of the Hydration of the A Conformation of the DNA Double Helix

A High Angle Neutron Fibre Diffraction Study of the Hydration of the A Conformation of the DNA Double Helix

Relative Stabilities and Transitions of DNA Conformations in 1:1 Electrolytes: A Theoretical Study

Infrared linear dichroism of oriented DNA-ligand complexes prepared with the wet-spinning method

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