Advanced

Effects of salt concentrations and bending energy on the extent of ejection of phage genomes

Evilevitch, Alex LU ; Fang, Li Tai; Yoffe, Aron; Castelnovo, Martin; Rau, Donald C.; Parsegian, V. Adrian; Gelbart, William M. and Knobler, Charles M. (2008) In Biophysical Journal 94(3). p.1110-1120
Abstract
Recent work has shown that pressures inside dsDNA phage capsids can be as high as many tens of atmospheres; it

is this pressure that is responsible for initiation of the delivery of phage genomes to host cells. The forces driving ejection of the

genome have been shown to decrease monotonically as ejection proceeds, and hence to be strongly dependent on the genome

length. Here we investigate the effects of ambient salts on the pressures inside phage-l, for the cases of mono-, di-, and tetravalent

cations, and measure how the extent of ejection against a fixed osmotic pressure (mimicking the bacterial cytoplasm) varies with

cation concentration. We find, for example, that the ejection... (More)
Recent work has shown that pressures inside dsDNA phage capsids can be as high as many tens of atmospheres; it

is this pressure that is responsible for initiation of the delivery of phage genomes to host cells. The forces driving ejection of the

genome have been shown to decrease monotonically as ejection proceeds, and hence to be strongly dependent on the genome

length. Here we investigate the effects of ambient salts on the pressures inside phage-l, for the cases of mono-, di-, and tetravalent

cations, and measure how the extent of ejection against a fixed osmotic pressure (mimicking the bacterial cytoplasm) varies with

cation concentration. We find, for example, that the ejection fraction is halved in 30 mM Mg21 and is decreased by a factor of 10

upon addition of 1 mM spermine. These effects are calculated from a simple model of genome packaging, using DNA-DNA

repulsion energies as determined independently from x-ray diffraction measurements on bulk DNA solutions. By comparing the

measured ejection fractions with values implied from the bulk DNA solution data, we predict that the bending energy makes the d-

spacings inside the capsid larger than those for bulk DNA at the same osmotic pressure. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biophysical Journal
volume
94
issue
3
pages
1110 - 1120
publisher
Cell Press
external identifiers
  • wos:000252243200036
  • scopus:38549093508
ISSN
1542-0086
DOI
10.1529/biophysj.107.115345
language
English
LU publication?
yes
id
91b3afcf-aa7e-4aea-b16c-637b61687e00 (old id 947491)
date added to LUP
2008-01-24 17:44:40
date last changed
2017-09-10 03:47:38
@article{91b3afcf-aa7e-4aea-b16c-637b61687e00,
  abstract     = {Recent work has shown that pressures inside dsDNA phage capsids can be as high as many tens of atmospheres; it <br/><br>
is this pressure that is responsible for initiation of the delivery of phage genomes to host cells. The forces driving ejection of the <br/><br>
genome have been shown to decrease monotonically as ejection proceeds, and hence to be strongly dependent on the genome <br/><br>
length. Here we investigate the effects of ambient salts on the pressures inside phage-l, for the cases of mono-, di-, and tetravalent <br/><br>
cations, and measure how the extent of ejection against a fixed osmotic pressure (mimicking the bacterial cytoplasm) varies with <br/><br>
cation concentration. We find, for example, that the ejection fraction is halved in 30 mM Mg21 and is decreased by a factor of 10 <br/><br>
upon addition of 1 mM spermine. These effects are calculated from a simple model of genome packaging, using DNA-DNA <br/><br>
repulsion energies as determined independently from x-ray diffraction measurements on bulk DNA solutions. By comparing the <br/><br>
measured ejection fractions with values implied from the bulk DNA solution data, we predict that the bending energy makes the d- <br/><br>
spacings inside the capsid larger than those for bulk DNA at the same osmotic pressure.},
  author       = {Evilevitch, Alex and Fang, Li Tai and Yoffe, Aron and Castelnovo, Martin and Rau, Donald C. and Parsegian, V. Adrian and Gelbart, William M. and Knobler, Charles M.},
  issn         = {1542-0086},
  language     = {eng},
  number       = {3},
  pages        = {1110--1120},
  publisher    = {Cell Press},
  series       = {Biophysical Journal},
  title        = {Effects of salt concentrations and bending energy on the extent of ejection of phage genomes},
  url          = {http://dx.doi.org/10.1529/biophysj.107.115345},
  volume       = {94},
  year         = {2008},
}