Motile behavior of bacteria

Flagellated bacteria possess a remarkable motility system based on a reversible rotary motor linked by a flexible coupling (the proximal hook) to a thin helical propeller (the flagellar filament). The motor derives its energy from protons driven into the cell by chemical gradients or electrical fields. The direction of the motor rotation depends in part on signals generated by sensory systems, of which the best studied analyzes chemical stimuli. Our research group is trying to learn how the motor works, the nature of the signal that controls the motor's direction of rotation, and how this signal is processed by the chemical sensory system. These questions are being approached by a variety of molecular-genetic and physical techniques. The goal is an understanding of chemiosmotic coupling and sensory transduction at the molecular level. Click here for entire article: Berg, H.C. (2003) "The rotary motor of bacterial flagella." Annu. Rev. Biochem. 72, 19-54.

Also see "Revealing the mystery of the bacterial flagellum
— A self-assembling nanomachine with fine switching capability"

"Mechanical" animation of how the rotating joint works