The mechanism of DNA ejection in the Bacillus anthracis spore-binding phage 8a revealed by cryo-electron tomography

Xiaofeng Fu, Michael H. Walter, Angel Paredes, Marc C. Morais, Jun Liu

Research output: Contribution to journalArticle

13 Scopus citations


The structure of the Bacillus anthracis spore-binding phage 8a was determined by cryo-electron tomography. The phage capsid forms a T = 16 icosahedron attached to a contractile tail via a head-tail connector protein. The tail consists of a six-start helical sheath surrounding a central tail tube, and a structurally novel baseplate at the distal end of the tail that recognizes and attaches to host cells. The parameters of the icosahedral capsid lattice and the helical tail sheath suggest protein folds for the capsid and tail-sheath proteins, respectively, and indicate evolutionary relationships to other dsDNA viruses. Analysis of 2518 intact phage particles show four distinct conformations that likely correspond to four sequential states of the DNA ejection process during infection. Comparison of the four observed conformations suggests a mechanism for DNA ejection, including the molecular basis underlying coordination of tail sheath contraction and genome release from the capsid.

Original languageEnglish (US)
Pages (from-to)141-148
Number of pages8
Issue number2
StatePublished - Dec 20 2011



  • Bacillus anthracis
  • Bacteriophage
  • Base plate
  • Contractile tail
  • Cryo-electron tomography
  • DNA ejection
  • Myoviridae
  • Phage infection
  • Tail contraction
  • Tail sheath

ASJC Scopus subject areas

  • Virology

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