DNA Packaging-Associated Hyper-Capsid Expansion of Bacteriophage T3

Philip Serwer, Elena T. Wright, Kevin Hakala, Susan T. Weintraub, Min Su, Wen Jiang

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Evidence that in vivo bacteriophage T3 DNA packaging includes capsid hyper-expansion that is triggered by lengthening of incompletely packaged DNA (ipDNA) is presented here. This evidence includes observation that some of the longer ipDNAs in T3-infected cells are packaged in ipDNA-containing capsids with hyper-expanded outer shells (HE ipDNA-capsids). In addition, artificially induced hyper-expansion is observed for the outer shell of a DNA-free capsid. Detection and characterization of HE ipDNA-capsids are based on two-dimensional, non-denaturing agarose gel electrophoresis, followed by structure determination with electron microscopy and protein identification with SDS-PAGE/mass spectrometry. After expulsion from HE ipDNA-capsids, ipDNA forms sharp bands during gel electrophoresis. The following hypotheses are presented: (1) T3 has evolved feedback-initiated, ATP-driven capsid contraction/hyper-expansion cycles that accelerate DNA packaging when packaging is slowed by increase in the packaging-resisting force of the ipDNA and (2) each gel electrophoretic ipDNA band reflects a contraction/hyper-expansion cycle.

Original languageEnglish (US)
Pages (from-to)361-374
Number of pages14
JournalJournal of Molecular Biology
Issue number2
StatePublished - Mar 26 2010


  • bacteriophage DNA packaging motor
  • biological energy transduction
  • electron microscopy
  • mass spectrometry
  • two-dimensional agarose gel electrophoresis

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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