7RYE

Cryo-EM structure of the needle filament-tip complex of the Salmonella type III secretion injectisome

Summary for 7RYE

• Entry DOI: 10.2210/pdb7rye/pdb
• EMDB information: 24735
• Descriptor: Protein PrgI, Cell invasion protein SipD (2 entities in total)
• Functional Keywords: protein secretion, bacterial pathogenesis, organelle assembly, cell invasion
• Biological source: Salmonella enterica subsp. enterica serovar Typhimurium; More
• Total number of polymer chains: 24
• Total formula weight: 354138.23

Authors

Guo, E.Z.,Galan, J.E. (deposition date: 2021-08-25, release date: 2021-11-10, Last modification date: 2025-05-28)

Primary citation

Guo, E.Z.,Galan, J.E.
Cryo-EM structure of the needle filament tip complex of the Salmonella type III secretion injectisome.
Proc.Natl.Acad.Sci.USA, 118:-, 2021

PubMed Abstract: Type III secretion systems are multiprotein molecular machines required for the virulence of several important bacterial pathogens. The central element of these machines is the injectisome, a ∼5-Md multiprotein structure that mediates the delivery of bacterially encoded proteins into eukaryotic target cells. The injectisome is composed of a cytoplasmic sorting platform, and a membrane-embedded needle complex, which is made up of a multiring base and a needle-like filament that extends several nanometers from the bacterial surface. The needle filament is capped at its distal end by another substructure known as the tip complex, which is crucial for the translocation of effector proteins through the eukaryotic cell plasma membrane. Here we report the cryo-EM structure of the Typhimurium needle tip complex docked onto the needle filament tip. Combined with a detailed analysis of structurally guided mutants, this study provides major insight into the assembly and function of this essential component of the type III secretion protein injection machine.

PubMed: 34706941
DOI: 10.1073/pnas.2114552118

Experimental method

ELECTRON MICROSCOPY (3.9 Å)