Single-molecule interrogation of a bacterial sugar transporter allows the discovery of an extracellular inhibitor

Capsular polysaccharides (CPS) enclose many pathogenic strains of Escherichia coli, protecting the bacteria from the host. Here, an extracellular blocker of Wza, a pore-forming protein that transports CPS to the cell surface, has been discovered by single-channel electrical recording. Treatment with the blocker exposes the bacterial cell surface and thereby facilitates killing by the human immune system.