Yale reveals molecular structure of cholera flagella ^{CEFR B1}

Cholera kills around 95,000 people each year and is caused by the bacterium Vibrio cholerae, which infects cells in the small intestine. The bacteria use flagella—tail-like structures—to move and reach those cells. Scientists have known the proteins that make these flagella for decades, but how the pieces fit together remained unclear.

Yale School of Medicine researchers reported new findings in Nature Microbiology that reveal the molecular structure of flagella in live V. cholerae. Jun Liu was the senior author and Wangbiao Guo was the first author. The team developed a microscopy approach to view the flagella while the bacteria were alive. Guo and a collaborator made mutated bacteria whose flagella proteins were designed to light up, then froze the cells in liquid ethane and imaged them with a powerful electron microscope at near-atomic resolution.

The images showed how each of four flagella proteins fits inside a hydrophilic protective sheath, which had blocked earlier studies. The sheath may act like a lubricant, allowing the flagellum to rotate independently from the outer casing. This slippery system could help V. cholerae move faster through liquid and push past the mucus layer to infect cells. Liu said the techniques could lead to new drugs that target flagella.