In recent years, significant progress has been made towards uncovering the physical mechanisms of low-hydration polymorphism in double-helical DNA. The effect appears to be mechanistically similar in different biological systems, and it is due to the ability of water to form spanning H-bonded networks around biomacromolecules via a quasi-two-dimensional percolation transition. In the case of DNA, disintegration of the spanning H-bonded network leads to electrostatic condensation of DNA strands because, below the percolation threshold, water loses its high dielectric permittivity, whereas the concentration of neutralizing counterions becomes high. In this Concept article arguments propose that this simple electrostatic mechanism represents the universal origin of low-hydration polymorphism in DNA.
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http://dx.doi.org/10.1002/cphc.200800446 | DOI Listing |
Chemistry
March 2017
GZG, Abt. Kristallographie, Georg-August-Universität Göttingen, Goldschmidtstr. 1, 37077, Göttingen, Germany.
In situ high-pressure crystallization and diffraction techniques have been applied to obtain two very structurally distinct semi-clathrates of the tert-butylamine-water system with hydration numbers 5.65 and 5.8, respectively, thereby considerably reducing a notable hydration gap between the monohydrate and the 71/4 -hydrate that results when crystallization space is explored by temperature alone.
View Article and Find Full Text PDFChemphyschem
December 2008
CNRS UPR9080, Institut de Biologie Physico-Chimique, 13, rue Pierre et Marie Curie, Paris, France.
In recent years, significant progress has been made towards uncovering the physical mechanisms of low-hydration polymorphism in double-helical DNA. The effect appears to be mechanistically similar in different biological systems, and it is due to the ability of water to form spanning H-bonded networks around biomacromolecules via a quasi-two-dimensional percolation transition. In the case of DNA, disintegration of the spanning H-bonded network leads to electrostatic condensation of DNA strands because, below the percolation threshold, water loses its high dielectric permittivity, whereas the concentration of neutralizing counterions becomes high.
View Article and Find Full Text PDFJ Am Chem Soc
January 2008
Physical Chemistry, Technical University of Dortmund, Otto-Hahn-Str. 6, Dortmund, D-44227, Germany.
The dynamics of ions and water at the surface of DNA are studied by computer simulations in a wide range of hydrations involving the zone of low-hydration polymorphism in DNA. The long-range mobility of ions exhibits a stepwise increase at three distinct hydration levels. The first of them is close to the midpoint of the water percolation transition as well as the midpoint of the transition between A- and B-DNA forms.
View Article and Find Full Text PDFJ Phys Chem B
March 2007
Physical Chemistry, Dortmund University, Otto-Hahn-Str. 6, Dortmund D-44227, Germany.
The hydrogen-bonded networks of water at the surface of a model DNA molecule are analyzed. At low hydrations, only small water clusters are attached to the DNA surface, whereas, at high hydrations, it is homogeneously covered by a spanning water network. The spanning water network is formed via a percolation transition at an intermediate hydration number of about 15 water molecules per nucleotide, which is very close to the midpoint of polymorphic transitions between A- and B-forms of the double helix.
View Article and Find Full Text PDFJ Chem Theory Comput
March 2005
CNRS UPR9080, Institut de Biologie Physico-Chimique, 13, rue Pierre et Marie Curie, Paris 75005, France.
Dynamics of the polymorphic A↔B transitions in DNA is compared for two polypurine sequences, poly(dA).poly(dT) and poly(dG).poly(dC), long known to exhibit contrasting properties in experiments.
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