pH-dependent allosteric remodeling of a bacterial riboswitch couples alkaline activation to metal sensing.

Alkaline pH enhances Mn2+ sensitivity in Escherichia coli alx riboswitch by remodeling its allosteric structure, enabling combined metal and proton sensing.

• Why it matters: Understanding how bacteria adapt to environmental stresses like alkalinity and metal fluctuations is crucial for insights into microbial survival and regulation. The mechanisms linking pH and metal sensing in riboswitches remain unclear, limiting our knowledge of bacterial stress responses.
• What they did: The study used single-molecule FRET and molecular dynamics simulations to investigate the alx riboswitch, revealing that pH influences its conformational states and Mn2+ binding, with key structural elements identified as essential for pH-dependent activation.
• The result: Findings demonstrate that pH-dependent allosteric remodeling enables the riboswitch to integrate metal and proton signals, providing a sophisticated mechanism for bacterial adaptation to alkaline stress and metal homeostasis.