Atomic structures of a bactericidal contractile nanotube in its pre- and postcontraction states

Peng Ge, Dean Scholl, Petr Leiman, Xuekui Yu, Jeff F. Miller, Z. Hong Zhou

Research output: Contribution to journalArticle

81 Scopus citations


R-type pyocins are representatives of contractile ejection systems, a class of biological nanomachines that includes, among others, the bacterial type VI secretion system (T6SS) and contractile bacteriophage tails. We report atomic models of the Pseudomonas aeruginosa precontraction pyocin sheath and tube, and the postcontraction sheath, obtained by cryo-EM at 3.5-Å and 3.9-Å resolutions, respectively. The central channel of the tube is negatively charged, in contrast to the neutral and positive counterparts in T6SSs and phage tails. The sheath is interwoven by long N- and C-terminal extension arms emanating from each subunit, which create an extensive two-dimensional mesh that has the same connectivity in the extended and contracted state of the sheath. We propose that the contraction process draws energy from electrostatic and shape complementarities to insert the inner tube through bacterial cell membranes to eventually kill the bacteria.

Original languageEnglish (US)
Pages (from-to)377-382
Number of pages6
JournalNature Structural and Molecular Biology
Issue number5
StatePublished - May 11 2015
Externally publishedYes


ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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