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Virology. 2015 Nov;485:128-34. doi: 10.1016/j.virol.2015.07.006. Epub 2015 Aug 1.

Bacteriophage P22 ejects all of its internal proteins before its genome.

Author information

1
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
2
Michigan State University, Department of Biochemistry and Molecular Biology, East Lansing, MI 48824, USA.
3
Michigan State University, Department of Biochemistry and Molecular Biology, East Lansing, MI 48824, USA; Michigan State University, Department of Microbiology and Molecular Genetics, East Lansing, MI 48824, USA.
4
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA. Electronic address: gelbart@chem.ucla.edu.
5
Michigan State University, Department of Biochemistry and Molecular Biology, East Lansing, MI 48824, USA. Electronic address: kparent@msu.edu.

Abstract

Double-stranded DNA bacteriophages are highly pressurized, providing a force driving ejection of a significant fraction of the genome from its capsid. In P22-like Podoviridae, internal proteins ("E proteins") are packaged into the capsid along with the genome, and without them the virus is not infectious. However, little is known about how and when these proteins come out of the virus. We employed an in vitro osmotic suppression system with high-molecular-weight polyethylene glycol to study P22 E protein release. While slow ejection of the DNA can be triggered by lipopolysaccharide (LPS), the rate is significantly enhanced by the membrane protein OmpA from Salmonella. In contrast, E proteins are not ejected unless both OmpA and LPS are present and their ejection when OmpA is present is largely complete before any genome is ejected, suggesting that E proteins play a key role in the early stage of transferring P22 DNA into the host.

KEYWORDS:

Bacteriophage infectivity; Genome ejection; Internal protein ejection; Osmotic suppression; Receptors

PMID:
26245366
PMCID:
PMC4619139
DOI:
10.1016/j.virol.2015.07.006
[Indexed for MEDLINE]
Free PMC Article

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