6AHQ

Structure of the 40-167 fragment of FliL

Summary for 6AHQ

• Entry DOI: 10.2210/pdb6ahq/pdb
• Descriptor: Flagellar protein FliL (1 entity in total)
• Functional Keywords: flagellar motor protein, motor protein
• Biological source: Vibrio alginolyticus
• Total number of polymer chains: 20
• Total formula weight: 280514.28

Authors

Takekawa, N.,Isumi, M.,Sakuma, M.,Kojima, S.,Homma, M.,Imada, K. (deposition date: 2018-08-20, release date: 2019-03-06, Last modification date: 2023-11-22)

Primary citation

Takekawa, N.,Isumi, M.,Terashima, H.,Zhu, S.,Nishino, Y.,Sakuma, M.,Kojima, S.,Homma, M.,Imada, K.
Structure ofVibrioFliL, a New Stomatin-like Protein That Assists the Bacterial Flagellar Motor Function.
MBio, 10:-, 2019

PubMed Abstract: Many motile bacteria swim or swarm using a filamentous rotating organelle, the flagellum. FliL, a component protein of the flagellar motor, is known to enhance the motor performance under high-load conditions in some bacteria. Here we determined the structure of the periplasmic region of FliL (FliL) of the polar flagellum of FliL shows a remarkable structural similarity to the stomatin/prohibitin/flotillin/HflK/C (SPFH) domain of stomatin family proteins, some of which are involved in modulation of ion channel activities in various organisms. FliL forms a ring assembly in the crystal with an inner diameter of around 8 nm, which is comparable to the size of the stator unit. Mutational analyses suggest that the FliL ring forms a complex with the stator unit and that the length of the periplasmic linkers of FliL and the stator B-subunit is essential for the complex formation. We propose a model of the FliL-stator complex to discuss how FliL modulates stator function in the bacterial flagellar motor under conditions of high viscosity. Some flagellated bacteria regulate motor torque in response to the external load change. This behavior is critical for survival, but the mechanism has remained unknown. Here, we focused on a key protein, FliL of , and solved the crystal structure of its periplasmic region (FliL). FliL reveals striking structural similarity to a conserved domain of stomatin, which is involved in ion channel regulation in some organisms, including mammals. FliL forms a ring with an inner diameter that is comparable in size to the stator unit. The mutational analyses suggested that the presence of the ring-like assembly of FliL around the stator unit enhances the surface swarming of cells. Our study data also imply that the structural element for the ion channel regulation is conserved from bacteria to mammals.

PubMed: 30890608
DOI: 10.1128/mBio.00292-19

Experimental method

X-RAY DIFFRACTION (3.398 Å)