6CH3

Crystal structure of the cytoplasmic domain of FlhA and FliS-FliC complex

Summary for 6CH3

• Entry DOI: 10.2210/pdb6ch3/pdb
• Descriptor: Flagellar biosynthesis protein FlhA, Flagellar secretion chaperone FliS,Flagellin (3 entities in total)
• Functional Keywords: flagellar, structural protein
• Biological source: Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720); More
• Total number of polymer chains: 2
• Total formula weight: 57422.26

Authors

Xing, Q.,Shi, K.,Kalodimos, C.G. (deposition date: 2018-02-21, release date: 2018-05-16, Last modification date: 2024-03-13)

Primary citation

Xing, Q.,Shi, K.,Portaliou, A.,Rossi, P.,Economou, A.,Kalodimos, C.G.
Structures of chaperone-substrate complexes docked onto the export gate in a type III secretion system.
Nat Commun, 9:1773-1773, 2018

PubMed Abstract: The flagellum and the injectisome enable bacterial locomotion and pathogenesis, respectively. These nanomachines assemble and function using a type III secretion system (T3SS). Exported proteins are delivered to the export apparatus by dedicated cytoplasmic chaperones for their transport through the membrane. The structural and mechanistic basis of this process is poorly understood. Here we report the structures of two ternary complexes among flagellar chaperones (FliT and FliS), protein substrates (the filament-capping FliD and flagellin FliC), and the export gate platform protein FlhA. The substrates do not interact directly with FlhA; however, they are required to induce a binding-competent conformation to the chaperone that exposes the recognition motif featuring a highly conserved sequence recognized by FlhA. The structural data reveal the recognition signal in a class of T3SS proteins and provide new insight into the assembly of key protein complexes at the export gate.

PubMed: 29720631
DOI: 10.1038/s41467-018-04137-4

Experimental method

X-RAY DIFFRACTION (2.68 Å)