Peptidoglycan is a dynamic macromolecule that needs to be modulated along the bacterial cell cycle in order to remain protective during cell elongation and cell division. This research axis focuses on understanding the dynamics of peptidoglycan synthesis across multiple species of Gram negative and Gram positive bacteria. It aims to characterize the schematics of new peptidoglycan strands insertion in the existing mesh. We use a combination of liquid chromatography, high-resolution mass spectrometry, and fluorescence microscopy to decipher and visualize the mode of peptidoglycan expansion, in wild-type cells or in combination with drugs or mutations that affect the cell cycle. Interactions between newly synthetized peptidoglycan strands and the protective mesh are quantified by a newly developed pulse-labelling method, using stable isotopes of carbon and nitrogen. Because peptidoglycan remodeling is mediated by the coordinated action of synthetic and lytic enzymes, providing tight regulation to avoid erratic peptidoglycan lysis, this project also aims to evaluate the participation of lytic enzymes in peptidoglycan expansion.

Associated publications:

• Anoyatis-Pelé C, Bellard L, Sezonov G, Morlot C, Hugonnet JE, Arthur M. (2025). Role of endopeptidases in lateral cell wall expansion in Escherichia coli. Cell Rep, Oct 28;44(10):116389

• Liang, Y., Bellard, L., Wong, S.Y., Morlot, C., Hugonnet, J.E., Rusconi, F., and Arthur, M. (2025). Mechanism of lateral cell wall expansion at a constant diameter in Bacillus subtilis. Nat Commun, Jul 19;16(1):6671.

• Liang, Y., Hugonnet, J.E., Rusconi, F., and Arthur, M. (2024). Peptidoglycan-tethered and free forms of the Braun lipoprotein are in dynamic equilibrium in Escherichia coli. Elife 12.

• Atze, H., Liang, Y., Hugonnet, J.E., Gutierrez, A., Rusconi, F., and Arthur, M. (2022). Heavy isotope labeling and mass spectrometry reveal unexpected remodeling of bacterial cell wall expansion in response to drugs. Elife 11.