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Directed evolution of SecB chaperones toward toxin-antitoxin systems

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Sala Ambre Julie, Bordes Patricia, Ayala Sara, Slama Nawel, Tranier Samuel, Coddeville Michèle, Cirinesi Anne-Marie, Castanié-Cornet Marie-Pierre, Mourey Lionel, Genevaux Pierre,
Project Pangenomic and comprehensive analysis of the relationship between bacterial toxin-antitoxin systems and antibiotic phenotype
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Original article (peer-reviewed)

Journal Proceedings of the National Academy of Sciences
Volume (Issue) 114(47)
Page(s) 12584 - 12589
Title of proceedings Proceedings of the National Academy of Sciences
DOI 10.1073/pnas.1710456114


SecB chaperones assist protein export in bacteria. However, certain SecB family members have diverged to become specialized toward the control of toxin-antitoxin (TA) systems known to promote bacterial adaptation to stress and persistence. In such tripartite TA-chaperone (TAC) systems, the chaperone was shown to assist folding and to prevent degradation of its cognate antitoxin, thus facilitating inhibition of the toxin. Here, we used both the export chaperone SecB of Escherichia coli and the tripartite TAC system of Mycobacterium tuberculosis as a model to investigate how generic chaperones can specialize toward the control of TA systems. Through directed evolution of SecB, we have identified and characterized mutations that specifically improve the ability of SecB to control our model TA system without affecting its function in protein export. Such a remarkable plasticity of SecB chaperone function suggests that its substrate binding surface can be readily remodeled to accommodate specific clients.