The intestinal bacterium E. coli can adapt to changes in its surroundings. Leiden scientists have discovered how the H-NS protein makes this possible. This new knowledge can be an important starting point in combatting bacteria and diseases such as peritonitis. Publication 2 October in the journal eLife.

E.coli is responsible for all kinds of diseases, including peritonitis, and is also one of the causes of food poisoning. This bacterium contains the protein H-NS, which can switch the genes of the bacterium on and off. Switching these genes on and off allows the bacterium to survive changes in its surroundings, such as a rise or drop in temperature. Ramon van der Valk from the Leiden Institute of Chemistry has discovered how exactly this process works. This knowledge could be the basis for developing new antibiotics to combat the E. coli bacterium (and others).

H-NS itself detects changes in the environment

'As long ago as in 2000, my colleague Remus Dame discovered how the H-NS protein switches particular genes in the E. coli bacterium off,' Van der Valk explained. 'But we didn't know how these genes can be switched on again. It now appears that H-NS receives signals from the environment if there is a change in the surroundings of the bacterium, and as a reaction to this switches the genes on again.' Thanks to the work of Van der Valk and his colleagues, this process has now been charted. H-NS itself appears to be able to detect changes, including changes in temperature and sodium content.

The study was a partnership between the Universities of Leiden, Amsterdam, and Heidelberg (D), where the researchers applied a multidisciplinary approach to examine how H-NS works and its effect on the environment. 'The study focused on different signals from the environment to which the protein reacted, such as temperature, pH or changes in the salt concentration. By using biochemical and biophysical methods in combination with computer simulations, we were able to analyse the effect of these symbols on H-NS. In a test tube, we were then able to influence the way that N-NS binds to DNA.'