The Cryo-Electron Microscopy Structure of the Type 1 Chaperone-Usher Pilus Rod

Chaperone-usher pili are long, polymeric protein fibres displayed on the surface of many bacterial pathogens. These critical virulence factors allow bacteria to specifically attach to host cells during infection. The type 1 and P pili of uropathogenic Escherichia coli (UPEC) play important roles during UPECs colonisation of the urinary tract, mediating bacterial attachment to the bladder and kidney, respectively. Also, their biomechanical properties that allow them to reversibly uncoil in response to flow-induced forces are critical for UPECs ability to retain a foothold in the unique and hostile environment of the urinary tract. Here we provide the 4.2 [A] resolution cryo-electron microscopy (cryo-EM) structure of the type 1 pilus rod, which together with the previous structure of the P pilus rod, enables us to understand the remarkable \"spring-like\" properties of chaperone-usher pili in more detail.