6AI0

Structure of the 328-692 fragment of FlhA (orthorhombic form)

Summary for 6AI0

• Entry DOI: 10.2210/pdb6ai0/pdb
• Related: 3A5I
• Descriptor: Flagellar biosynthesis protein FlhA, (4R)-2-METHYLPENTANE-2,4-DIOL, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: flagellar type iii secretion, protein transport
• Biological source: Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)
• Total number of polymer chains: 2
• Total formula weight: 81699.87

Authors

Ogawa, Y.,Kinoshita, M.,Minamino, T.,Imada, K. (deposition date: 2018-08-21, release date: 2019-03-20, Last modification date: 2023-11-22)

Primary citation

Inoue, Y.,Ogawa, Y.,Kinoshita, M.,Terahara, N.,Shimada, M.,Kodera, N.,Ando, T.,Namba, K.,Kitao, A.,Imada, K.,Minamino, T.
Structural Insights into the Substrate Specificity Switch Mechanism of the Type III Protein Export Apparatus.
Structure, 27:965-, 2019

PubMed Abstract: Bacteria use a type III protein export apparatus for construction of the flagellum, which consists of the basal body, the hook, and the filament. FlhA forms a homo-nonamer through its C-terminal cytoplasmic domains (FlhA) and ensures the strict order of flagellar assembly. FlhA goes through dynamic domain motions during protein export, but it remains unknown how it occurs. Here, we report that the FlhA(G368C) mutation biases FlhA toward a closed form, thereby reducing the binding affinity of FlhA for flagellar export chaperones in complex with their cognate filament-type substrates. The G368C mutations also restrict the conformational flexibility of a linker region of FlhA (FlhA), suppressing FlhA ring formation. We propose that interactions of FlhA with its neighboring subunit converts FlhA in the ring from a closed conformation to an open one, allowing the chaperon/substrate complexes to bind to the FlhA ring to form the filament at the hook tip.

PubMed: 31031200
DOI: 10.1016/j.str.2019.03.017

Experimental method

X-RAY DIFFRACTION (2.4 Å)