Scientists at the University of York have characterised an important new step in the mechanism used by bacteria to evade our immune system.

It is an ‘invisibility cloak’ which means that bacteria like Haemophilus influenzae, a common cause of ear infections in children, can move about the body without the risk of being attacked by the immune system.

A multidisciplinary research team from the Departments of Biology and Chemistry at York have been studying how bacteria capture the molecule used to make the ‘cloak’, called sialic acid.

The researchers have now discovered an enzymatic activity that helps in the more efficient capture of sialic acids released from our cell surfaces. As well as using the sialic acid to make the ‘invisibility cloak’ other bacteria use similar methods to capture sialic acid as a simple food source, so are literally eating us from the inside!

Dr Gavin Thomas, of the Department of Biology, who led the research said: "This novel enzyme, as well as other steps required for the formation of the 'invisibility cloak' that we have discovered in York, now offers the chance to develop novel antimicrobials against these bacteria."

The work, which was funded by the Biotechnology and Biological Sciences Research Council (BBSRC), was undertaken by Dr. Emmanuele Severi (Biology - Thomas lab) in collaboration with Dr. Jennifer Potts (Biology and Chemistry), Dr. Andrew Leech (Biology) and Professor Keith Wilson and Dr. Axel Müller (Chemistry and York Structural Biology Laboratory).

The team used the Centre for Magnetic Resonance based in the Department of Chemistry, and the Technology Facility in the Department of Biology.

The paper Sialic Acid Mutarotation Is Catalyzed by the Escherichia coli ß-Propeller Protein YjhT was recently published in the Journal of Biological Chemistry.