The DNA-binding protein H-NS is a pleiotropic gene regulator in gram-negative bacteria. Through its capacity to sense temperature and other environmental factors, H-NS allows pathogens like Salmonella to adapt their gene expression to their presence inside or outside warm-blooded hosts. To investigate how this sensing mechanism may have evolved to fit different bacterial lifestyles, we compared H-NS orthologs from bacteria that infect humans, plants, and insects, and from bacteria that live on a deep-sea hypothermal vent. The combination of biophysical characterization, high-resolution proton-less NMR spectroscopy and molecular simulations revealed, at an atomistic level, how the same general mechanism was adapted to specific habitats and lifestyles. In particular, we demonstrate how environment-sensing characteristics arise from specifically positioned intra- or intermolecular electrostatic interactions. Our integrative approach clarified the exact modus operandi for H-NS–mediated environmental sensing and suggests that this sensing mechanism resulted from the exaptation of an ancestral protein feature.
- Xiaochuan Zhao
- Jianing Li
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Yibing Shan, Antidote Health Foundation, United States
- Received: April 1, 2020
- Accepted: January 6, 2021
- Accepted Manuscript published: January 7, 2021 (version 1)
© 2021, Zhao et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.