1Q5Z

Crystal Structure of the C-terminal Actin Binding Domain of Salmonella Invasion Protein A (SipA)

Summary for 1Q5Z

• Entry DOI: 10.2210/pdb1q5z/pdb
• Descriptor: SipA (2 entities in total)
• Functional Keywords: cell invasion
• Biological source: Salmonella typhimurium
• Cellular location: Secreted: Q56027
• Total number of polymer chains: 1
• Total formula weight: 19454.94

Authors

Stebbins, C.E.,Lilic, M.,Galkin, V.E.,Orlova, A.,VanLoock, M.S.,Egelman, E.H. (deposition date: 2003-08-11, release date: 2003-10-07, Last modification date: 2024-02-14)

Primary citation

Lilic, M.,Galkin, V.E.,Orlova, A.,VanLoock, M.S.,Egelman, E.H.,Stebbins, C.E.
Salmonella SipA polymerizes actin by stapling filaments with nonglobular protein arms.
Science, 301:1918-1921, 2003

PubMed Abstract: Like many bacterial pathogens, Salmonella spp. use a type III secretion system to inject virulence proteins into host cells. The Salmonella invasion protein A (SipA) binds host actin, enhances its polymerization near adherent extracellular bacteria, and contributes to cytoskeletal rearrangements that internalize the pathogen. By combining x-ray crystallography of SipA with electron microscopy and image analysis of SipA-actin filaments, we show that SipA functions as a "molecular staple," in which a globular domain and two nonglobular "arms" mechanically stabilize the filament by tethering actin subunits in opposing strands. Deletion analysis of the tethering arms provides strong support for this model.

PubMed: 14512630
DOI: 10.1126/science.1088433

Experimental method

X-RAY DIFFRACTION (1.8 Å)