Osmotic pressure inhibition of DNA ejection from phage

Alex Evilevitch, Laurence Lavelle, Charles M. Knobler, Eric Raspaud, William M. Gelbart

Research output: Contribution to journalArticlepeer-review


Bacterial viral capsids in aqueous solution can be opened in vitro by addition of their specific receptor proteins, with consequent full ejection of their genomes. We demonstrate that it is possible to control the extent of this ejection by varying the external osmotic pressure. In the particular case of bacteriophage λ, the ejection is 50% inhibited by osmotic pressures (of polyethylene glycol) comparable to those operative in the cytoplasm of host bacteria; it is completely suppressed by a pressure of 20 atmospheres. Furthermore, our experiments monitor directly a dramatic decrease of the stress inside the unopened phage capsid upon addition of polyvalent cations to the host solution, in agreement with many recent theories of DNA interactions.

Original languageEnglish (US)
Pages (from-to)9292-9295
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number16
StatePublished - Aug 5 2003

ASJC Scopus subject areas

  • General

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