How Bacteria Form “Nano-Syringes”

Image courtesy of Volker Brinkmann, Diane Schad and Michael Kolbe

Bacterial pathogens can create transport channels that function similar to syringes, forming a pathway for injecting virulence factors into host cells. Researchers from the Max Planck Society and the Federal Institute for Materials Research and Testing have revealed the details of how the mechanism works. The scientists also were able to mimic the bacterial transport channel in a test tube, a breakthrough that could lead to novel drug delivery systems that target bacterial infections.

Syringes isolated from Shigella flexneri. Adding needle protein leads to a spontaneous prolongation of some needles. The bar corresponds to 100 nanometers. One nanometer corresponds to a millionth millimeter. Image courtesy of Christian Goosmann and Michael Kolbe.

In their experiments, the scientists studied the assembly of proteins into a needle in a test tube and were able to observe how how proteins were assembled into a syringe-like shape: The bacterium synthesises proteins in the cell interior, transports them through the syringe to the outside, and stacks them one after the other onto the tip of the growing needle. The researchers also demonstrated that the proteins change their three-dimensional structure during the assembly process. They were able to pinpoint the exact structural changes at the single amino acid level.

More information on the research is available from the Max Planck Society.

Tags: bacteria, Max Planck Society, nano-syringe