A combination of an array of atomic-level techniques has allowed researchers to show how changes in an environment-sensing protein enable bacteria to survive in different habitats, from the human gut to deep-sea hydrothermal vents.
“The study gives us unprecedented atomic-level insight into how bacteria adapt to changing conditions,” says Stefan Arold, professor of bioscience at KAUST. “To obtain these insights, we pushed the limits of three different methods of investigation and combined their results into a unified picture.”
The histone-like nucleoid-structuring (H-NS) protein allows bacteria to sense changes in their environment, such as changes in temperature and salinity. Previously, the team had shown how the intestinal pathogen Salmonella typhimurium uses H-NS to control its gene expression profile, enabling it to live optimally inside its warm-blooded host or outside in the soil.
The H-NS protein is also found in bacteria that do not experience massive temperature fluctuations, such as plant pathogens, insect symbionts and free-living microbes that inhabit deep-sea hydrothermal vents. Still puzzling, however, is how different bacteria have adapted the same sensing mechanism to suit a variety of lifestyles.
No single analysis technique has been able to unravel the inner workings of this mechanism and so, to gain a more integrated view, Arold assembled a diverse team from KAUST and international collaborators. Arold and Lukasz Jaremko, a molecular biochemist at KAUST, collaborated with Jianing Li from the University of Vermont to combine several methods: protonless nuclear magnetic resonance spectroscopy, all-atom molecular dynamics simulations and biophysics techniques. This synergistic approach allowed the researchers to analyze the reaction of different H-NS proteins to temperature and salinity on an atomistic level.
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