Topology and organization of the Salmonella typhimurium type III secretion needle complex components

PLoS Pathog. 2010 Apr 1;6(4):e1000824. doi: 10.1371/journal.ppat.1000824.


The correct organization of single subunits of multi-protein machines in a three dimensional context is critical for their functionality. Type III secretion systems (T3SS) are molecular machines with the capacity to deliver bacterial effector proteins into host cells and are fundamental for the biology of many pathogenic or symbiotic bacteria. A central component of T3SSs is the needle complex, a multiprotein structure that mediates the passage of effector proteins through the bacterial envelope. We have used cryo electron microscopy combined with bacterial genetics, site-specific labeling, mutational analysis, chemical derivatization and high-resolution mass spectrometry to generate an experimentally validated topographic map of a Salmonella typhimurium T3SS needle complex. This study provides insights into the organization of this evolutionary highly conserved nanomachinery and is the basis for further functional analysis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / ultrastructure*
  • Cryoelectron Microscopy
  • Macromolecular Substances
  • Membrane Transport Proteins / chemistry*
  • Membrane Transport Proteins / ultrastructure*
  • Salmonella typhimurium / chemistry*
  • Salmonella typhimurium / ultrastructure*


  • Bacterial Proteins
  • Macromolecular Substances
  • Membrane Transport Proteins
  • PrgH protein, Salmonella typhimurium
  • invG protein, Salmonella typhimurium