AI Article Synopsis

  • H-NS proteins sense changes in osmolarity and adjust their DNA binding properties, affecting gene transcription and genome organization in bacteria.
  • The study focuses on MvaT from Pseudomonas aeruginosa, showing it can exist in two states that impact its interaction with DNA— a half-opened state at low salt that forms filaments and a fully opened state at high salt that bridges DNA.
  • The mechanism behind this switching is related to ionic strength affecting electrostatic interactions, and similar charge distributions and interactions are found across the H-NS protein family, providing new insights into their osmosensitivity.

Article Abstract

H-NS proteins act as osmotic sensors translating changes in osmolarity into altered DNA binding properties, thus, regulating enterobacterial genome organization and genes transcription. The molecular mechanism underlying the switching process and its conservation among H-NS family members remains elusive. Here, we focus on the H-NS family protein MvaT from Pseudomonas aeruginosa and demonstrate experimentally that its protomer exists in two different conformations, corresponding to two different functional states. In the half-opened state (dominant at low salt) the protein forms filaments along DNA, in the fully opened state (dominant at high salt) the protein bridges DNA. This switching is a direct effect of ionic strength on electrostatic interactions between the oppositely charged DNA binding and N-terminal domains of MvaT. The asymmetric charge distribution and intramolecular interactions are conserved among the H-NS family of proteins. Therefore, our study establishes a general paradigm for the molecular mechanistic basis of the osmosensitivity of H-NS proteins.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039000PMC
http://dx.doi.org/10.1093/nar/gkz1226DOI Listing

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