Department of Life sciences
Research
What are flagella and cilia?
Flagella and cilia are hair-like appendages that extend from the cell body. Flagella are found in all kingdoms of life, enabling cell migration, adhesion, and mating. The building blocks of flagella and cilia are proteins organized in a distinct pattern. We use biochemical and structural techniques (primarily cryo-electron microscopy) to determine the internal structures of flagella and cilia. Revealing flagella architecture helps to decipher the mechanisms in which flagella and cilia beat.
Structure of the archaellum (archaellar flagellum)
The flagella of Archaea are termed archaella. They comprise up to a dozen proteins and are ~10 nm in diameter. In collaboration with Jerry Eichler's group, we determined the structure of the archaellum from the haloarchaeon Halobacterium salinarum, which thrives in extremely high salt concentrations (4 M NaCl!). The archaellum is built of archaellins, proteins decorated with N-linked tetrasachaarides, organized in a helical pattern. Shortening
these glycan groups doesn't affect archaellum structure but does lead to perturbed motility and archaella bundling. How do the glycans prevent archaella clustering?
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​Structure of the eukaryotic flagellum
The flagella of eukaryotic cells comprise hundreds of proteins and are ~250 nm in diameter. The core structure of the flagellum is a microtubule array termed "axoneme". How are the flagellar proteins organized within the axoneme? How does this architecture facilitate flagellar beating and cell motility?