Fig. 4.
Mechanisms of transmembrane signaling for E. coli chemoreceptors. a Mechanism of piston displacements [111–113], b mechanism of scissoring motions [12, 13, 15], c mechanism of rotation of helices [114], and d mechanism of supercoil unwinding of helices [115]. The helices of receptor periplasmic sensing domains are shown as blue cylinders. The attractants are shown in red