Modeling of DNA compaction by polycations

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In this work we study polycations as efficient compacting agents of a
medium size polyanion by means of Monte Carlo simulations. The systems
are characterized in terms of a conformational analysis in which shape,
overall dimensions, structure factors, radial distribution functions,
and the degree of accumulation of the compaction agent near the
polyanion are taken into consideration. Results show that the degree of
compaction depends on the size of the positive chais and their
number. The role of electrostatic interactions is paramount in the
compaction process, and an increase in the number of molecules of the
compacting agent or in the number of charges of each molecule leads to
collapse, which may be followed by some unfolding in situations of
overcharging. Compaction is associated with polycations promoting
bridging between different sites in the polyanion. When the total
charge of the polycations is significantly lower than that of the
polyanion, interaction produces only a small degree of intrachain
segregation in the latter, allowing for significant translational
motion of the compacting agent along the longer chain. However,
complete charge neutralization is not mandatory to achieve compact
forms. (C) 2003 American Institute of Physics.


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Ämnesklassifikation (UKÄ) – OBLIGATORISK

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Sidor (från-till)8150-8157
TidskriftJournal of Chemical Physics
StatusPublished - 2003
Peer review utfördJa