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

Vicki A M Gold; Ralf Salzer; Beate Averhoff; Werner Kühlbrandt

doi:10.7554/eLife.07380

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

Elife. 2015 May 21:4:e07380. doi: 10.7554/eLife.07380.

Authors

Vicki A M Gold¹, Ralf Salzer², Beate Averhoff², Werner Kühlbrandt¹

Affiliations

¹ Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
² Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany.

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 Thermus 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.

Keywords: DNA transporter; Thermus thermophilus; bacterial secretion; biophysics; electron cryo-tomography; structural biology; subtomogram averaging; type IV pilus.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cryoelectron Microscopy
Fimbriae, Bacterial / metabolism
Fimbriae, Bacterial / physiology*
Fimbriae, Bacterial / ultrastructure
Models, Molecular*
Multiprotein Complexes / metabolism*
Protein Conformation
Secretin / metabolism*
Thermus thermophilus / chemistry*

Substances

Multiprotein Complexes
Secretin

Grants and funding

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.