Related Experiment Video
Updated: Aug 8, 2026

Biophysical Characterization of Flagellar Motor Functions
Published on: January 18, 2017
Conformational switching in the flagellar filament of Salmonella typhimurium
1Department of Membrane and Ultrastructure Research, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Abstract:
The flagellar filament of the mutant Salmonella typhimurium strain SJW814 is straight, and has a right-handed twist like the filament of SJW1655. Three-dimensional reconstructions from electron micrographs of ice-embedded filaments reveal a flagellin subunit that has the same domain organization as that of SJW1655. Both show slight changes from the domain organization of the subunits from SJW1660, which possesses a straight, left-handed filament. This points to the possible role of changes in subunit conformation in the left-to-right-handed structural transition in filaments. Comparison of the left and right-handed filaments shows that the subunit's orientation and intersubunit bonding appear to change. The orientation of the subunit in the SJW814 filament is intermediate between that of SJW1655 and SJW1660. Its intermediate orientation may explain why the filaments of SJW1655 and SJW1660 are locked in one conformation, whereas the filament of SJW814 can be induced to switch by, for example, changes in pH and ionic strength.
Related Concept Videos
Cytoskeletal Proteins in Bacteria
Mechanism of Filopodia Formation
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Special Staining Techniques
Flagella and Motility in Bacteria
Fimbriae, Pili, and Axial Filaments
Chemotaxis in E. coli

