Strongly correlated electrostatics of vi

J Biol Phys (2013) 39:247–265

DOI 10.1007/s10867-013-9301-4

ORIGINAL PAPER

Strongly correlated electrostatics of viral

genome packaging

Toan T. Nguyen

Received: 10 December 2012 / Accepted: 16 January 2013 / Published online: 2 April 2013

Abstract The problem of viral packaging (condensation) and ejection from viral capsid

in the presence of multivalent counterions is considered. Experiments show divalent

counterions strongly influence the amount of DNA ejected from bacteriophage. In this

paper, the strong electrostatic interactions between DNA molecules in the presence of

multivalent counterions is investigated. It is shown that experiment results agree reasonably

well with the phenomenon of DNA reentrant condensation. This phenomenon is known

to cause DNA condensation in the presence of tri- or tetra-valent counterions. For divalent

counterions, the viral capsid confinement strongly suppresses DNA configurational entropy,

therefore the correlation between divalent counterions is strongly enhanced causing similar

effect. Computational studies also agree well with theoretical calculations.

Keywords DNA virus· DNA overcharging · Multivalent counterions·

Strongly correlated electrostatics

1 Introduction

The problem of DNA condensation in the presence of multivalent counterions has seen a

strong revival of interest in recent years. This is because of the need to develop effective

ways of gene delivery for the rapidly growing field of genetic therapy. DNA viruses such

as bacteriophages provide excellent study candidates for this purpose. One can package

genomic DNA into viruses, then deliver and release the molecule into targeted individual

T. T. Nguyen

Nano and Energy Center, Vietnam National University-Hanoi,

144 Xuan Thuy, Cau Giay Street, Hanoi, Vietnam

T. T. Nguyen (B)

School of Physics, Georgia Institute of Technology, 837 State Street,

Atlanta, GA 30332-0430, USA

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