Structure of a type IV pilus machinery in the open and closed state

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Abstract

Proteins of the secretin family form large macromolecular complexes, which assemble in the outer membrane of Gram-negative bacteria. Secretins are major components of type II and III secretion systems and are linked to extrusion of type IV pili (T4P) and to DNA uptake. By electron cryo-tomography of whole T. thermophilus cells, we determined the in situ structure of a T4P molecular machine in the open and the closed state. Comparison reveals a major conformational change whereby the N-terminal domains of the central secretin PilQ shift by ~30 Å, and two periplasmic gates open to make way for pilus extrusion. Furthermore, we determine the structure of the assembled pilus.

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Vicki A M Gold

Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany

For correspondence
vicki.gold@biophys.mpg.de

Competing interests
No competing interests declared.
Ralf Salzer

Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany

Competing interests
No competing interests declared.
Beate Averhoff

Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany

Competing interests
No competing interests declared.
Werner Kühlbrandt

Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany

Competing interests
Werner Kühlbrandt, Reviewing editor, eLife.

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