Toxin-antitoxin ratio sensing autoregulation of the Vibrio cholerae parDE2 module

Gabriela Garcia Rodriguez, Yana Girardin, Ranjan Kumar Singh, A.N. Volkov, Jeroen Van Dyck, Gopinath Muruganandam, Frank Sobott, Daniel Charlier, Remy Loris

Research output: Contribution to journalArticlepeer-review


The parDE family of toxin-antitoxin operons is ubiquitous in bacterial genomes, and in Vibrio cholerae is an essential component to maintain the presence of chromosome II. Here we show that transcription of the V. cholerae parDE2 operon is regulated in a toxin:antitoxin ratio-dependent manner using a molecular mechanism distinct from other type II TA systems. The repressor of the operon is identified as an assembly with a 6:2 stoichiometry with three interacting ParD2 dimers bridged by two ParE2 monomers. This assembly docks to a three-site operator containing 5’- GGTA-3’ motifs. Saturation of this TA complex with ParE2 toxin results in disruption of the interface between ParD2 dimers and the formation of a TA complex of 2:2 stoichiometry. The latter is operator binding-incompetent as it is incompatible with the required spacing of the ParD2 dimers on the operator.
Original languageEnglish
Article numbereadj2403
Number of pages14
JournalScience Advances
Issue number1
Publication statusPublished - Jan 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors.


  • Toxin-antitoxin
  • Structural biology
  • Transcription regulation
  • Molecular biophysics
  • Intrinsically disordered protein segment
  • Protein-DNA interaction
  • Gyrase poison


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