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Science. 2016 Mar 11;351(6278):aad2001. doi: 10.1126/science.aad2001. Epub 2016 Mar 10.

Architecture of the type IVa pilus machine.

Author information

1
California Institute of Technology, Pasadena, CA 91125, USA. Howard Hughes Medical Institute, Pasadena, CA 91125, USA.
2
Howard Hughes Medical Institute, Pasadena, CA 91125, USA.
3
Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
4
University of Utah, Salt Lake City, UT 84112, USA.
5
California Institute of Technology, Pasadena, CA 91125, USA. Howard Hughes Medical Institute, Pasadena, CA 91125, USA. jensen@caltech.edu.

Abstract

Type IVa pili are filamentous cell surface structures observed in many bacteria. They pull cells forward by extending, adhering to surfaces, and then retracting. We used cryo-electron tomography of intact Myxococcus xanthus cells to visualize type IVa pili and the protein machine that assembles and retracts them (the type IVa pilus machine, or T4PM) in situ, in both the piliated and nonpiliated states, at a resolution of 3 to 4 nanometers. We found that T4PM comprises an outer membrane pore, four interconnected ring structures in the periplasm and cytoplasm, a cytoplasmic disc and dome, and a periplasmic stem. By systematically imaging mutants lacking defined T4PM proteins or with individual proteins fused to tags, we mapped the locations of all 10 T4PM core components and the minor pilins, thereby providing insights into pilus assembly, structure, and function.

Comment in

PMID:
26965631
PMCID:
PMC5929464
DOI:
10.1126/science.aad2001
[Indexed for MEDLINE]
Free PMC Article

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