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Internal DNA pressure modifies stability of WT phage

Ivanovska, Irena; Wuite, Gijs; Jönsson, Bengt LU and Evilevitch, Alex LU (2007) In Proceedings of the National Academy of Sciences 104(23). p.9603-9608
Abstract
dsDNA in bacteriophages is highly stressed and exerts internal pressures of many atmospheres (1 atm = 101.3 kPa) on the capsid walls. We investigate the correlation between packaged DNA length in A phage (78-100% of WT DNA) and capsid strength by using an atomic force microscope indentation technique. We show that phages with WT DNA are twice as strong as shorter genome mutants, which behave like empty capsids, regardless of high internal pressure. Our analytical model of DNA-filled capsid deformation shows that, because of DNA-hydrating water molecules, an osmotic pressure exists inside capsids that increases exponentially when the packaged DNA density is close to WT phage. This osmotic pressure raises the WT capsid strength and is... (More)
dsDNA in bacteriophages is highly stressed and exerts internal pressures of many atmospheres (1 atm = 101.3 kPa) on the capsid walls. We investigate the correlation between packaged DNA length in A phage (78-100% of WT DNA) and capsid strength by using an atomic force microscope indentation technique. We show that phages with WT DNA are twice as strong as shorter genome mutants, which behave like empty capsids, regardless of high internal pressure. Our analytical model of DNA-filled capsid deformation shows that, because of DNA-hydrating water molecules, an osmotic pressure exists inside capsids that increases exponentially when the packaged DNA density is close to WT phage. This osmotic pressure raises the WT capsid strength and is approximately equal to the maximum breaking force of empty shells. This result suggests that the strength of the shells limits the maximal packaged genome length. Moreover, it implies an evolutionary optimization of WT phages allowing them to survive greater external mechanical stresses in nature. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
osmotic pressure, forces, DNA hydration, bacteriophage, atomic force microscopy, viral capsids
in
Proceedings of the National Academy of Sciences
volume
104
issue
23
pages
9603 - 9608
publisher
National Acad Sciences
external identifiers
  • wos:000247114100013
  • scopus:34547444408
ISSN
1091-6490
DOI
10.1073/pnas.0703166104
language
English
LU publication?
yes
id
cb8e8cd8-e558-4e2b-92dd-2d69227dc47b (old id 649057)
date added to LUP
2007-12-12 11:17:35
date last changed
2017-08-13 03:37:38
@article{cb8e8cd8-e558-4e2b-92dd-2d69227dc47b,
  abstract     = {dsDNA in bacteriophages is highly stressed and exerts internal pressures of many atmospheres (1 atm = 101.3 kPa) on the capsid walls. We investigate the correlation between packaged DNA length in A phage (78-100% of WT DNA) and capsid strength by using an atomic force microscope indentation technique. We show that phages with WT DNA are twice as strong as shorter genome mutants, which behave like empty capsids, regardless of high internal pressure. Our analytical model of DNA-filled capsid deformation shows that, because of DNA-hydrating water molecules, an osmotic pressure exists inside capsids that increases exponentially when the packaged DNA density is close to WT phage. This osmotic pressure raises the WT capsid strength and is approximately equal to the maximum breaking force of empty shells. This result suggests that the strength of the shells limits the maximal packaged genome length. Moreover, it implies an evolutionary optimization of WT phages allowing them to survive greater external mechanical stresses in nature.},
  author       = {Ivanovska, Irena and Wuite, Gijs and Jönsson, Bengt and Evilevitch, Alex},
  issn         = {1091-6490},
  keyword      = {osmotic pressure,forces,DNA hydration,bacteriophage,atomic force microscopy,viral capsids},
  language     = {eng},
  number       = {23},
  pages        = {9603--9608},
  publisher    = {National Acad Sciences},
  series       = {Proceedings of the National Academy of Sciences},
  title        = {Internal DNA pressure modifies stability of WT phage},
  url          = {http://dx.doi.org/10.1073/pnas.0703166104},
  volume       = {104},
  year         = {2007},
}