Science 320, 1636–1638 (2008)

A protein that allows the soil bacterium Bacillus subtilis to quickly halt its propeller-like propulsion and thus stick to a surface has been identified by Daniel Kearns of Indiana University in Bloomington and his colleagues. EpsE, the protein, seems to act like a clutch rather than a brake; it leaves the rotors that drive the bacterium's flagella unpowered but spinning freely rather than slowing them down.

The authors labelled B. subtilis's EpsE with a fluorescent protein and revealed that EpsE is associated with flagellar motors. They then attached bacteria to a surface by a flagellum. The cells rotated passively even when they produced EpsE, which would have prevented them from swimming.