Study reveals how bacterial sensor protein detects and responds to beta-lactam antibiotics
Researchers have uncovered the molecular mechanism by which the bacterial histidine kinase VbrK detects β-lactam antibiotics in Vibrio parahaemolyticus, triggering antibiotic resistance. The sensor domain undergoes redox-dependent acylation by β-lactams, a reversible chemical modification controlled by the oxidation state of two cysteine residues. Understanding this sensing mechanism could enable new strategies to block resistance activation and restore the effectiveness of existing antibiotics.
A new preprint study published on bioRxiv details how VbrK, a histidine kinase in the pathogen Vibrio parahaemolyticus, directly senses β-lactam antibiotics through a previously unrecognized chemical mechanism. The research shows that β-lactam binding to VbrK's periplasmic sensor domain depends critically on the redox state of two cysteine residues, C86 and C107, whose disulfide bond dynamics regulate whether the antibiotic can interact with the protein. Once a non-covalent complex forms, the sensor domain becomes covalently acylated by the β-lactam — a modification that is slowly reversed through de-acylation, releasing a hydrolyzed β-lactam ring. This reversibility means the bacterium can recover from induction of its resistance response once the antibiotic is cleared from the environment. The VbrK/VbrR two-component system ultimately drives expression of the serine β-lactamase CARB, a key resistance enzyme, making VbrK a potential therapeutic target for disabling resistance rather than killing bacteria directly.
What's missing
As a preprint, this study has not yet undergone formal peer review, so findings should be interpreted with caution. The study does not address whether this redox-dependent sensing mechanism is conserved across other gram-negative pathogens or whether it could be exploited in clinically relevant Vibrio strains. The in vivo relevance of the redox conditions required for VbrK activation — and how these relate to actual infection environments — is not discussed.
What different sources said
- bioRxivCenter
Redox-regulated cysteine acylation governs β-lactam sensing by the Vibrio histidine kinase VbrK
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