O-glycosylation as a novel control mechanism of peptidoglycan hydrolase activity

T. Rolain, E. Bernard, A. Beaussart, H. Degand, P. Courtin, W. Egge-Jacobsen, P.A. Bron, P. Morsomme, M. Kleerebezem, M.P. Chapot-Chartier, Y.F. Dufrêne, P. Hols

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Abstract

Acm2, the major autolysin of Lactobacillus plantarum, is a tripartite protein. Its catalytic domain is surrounded by an O-glycosylated N-terminal region rich in Ala, Ser, and Thr (AST domain), which is of low complexity and unknown function, and a C-terminal region composed of five SH3b peptidoglycan (PG) binding domains. Here, we investigate the contribution of these two accessory domains and of O-glycosylation to Acm2 functionality. We demonstrate that Acm2 is an N-acetylglucosaminidase and identify the pattern of O-glycosylation (21 mono-N-acetylglucosamines) of its AST domain. The O-glycosylation process is species-specific as Acm2 purified from Lactococcus lactis is not glycosylated. We therefore explored the functional role of O-glycosylation by purifying different truncated versions of Acm2 that were either glycosylated or non-glycosylated. We show that SH3b domains are able to bind PG and are responsible for Acm2 targeting to the septum of dividing cells, whereas the AST domain and its O-glycosylation are not involved in this process. Notably, our data reveal that the lack of O-glycosylation of the AST domain significantly increases Acm2 enzymatic activity, whereas removal of SH3b PG binding domains dramatically reduces this activity. Based on this antagonistic role, we propose a model in which access of the Acm2 catalytic domain to its substrate may be hindered by the AST domain where O-glycosylation changes its conformation and/or mediates interdomain interactions. To the best of our knowledge, this is the first time that O-glycosylation is shown to control the activity of a bacterial enzyme.
Original languageEnglish
Pages (from-to)22233-22247
JournalJournal of Biological Chemistry
Volume288
Issue number31
DOIs
Publication statusPublished - 2013

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Keywords

  • lactobacillus-plantarum wcfs1
  • diamino acid endopeptidase
  • lactococcus-lactis
  • teichoic-acids
  • staphylococcus-aureus
  • cell-separation
  • bacterial-peptidoglycan
  • n-acetylglucosaminidase
  • listeria-monocytogenes
  • protein glycosylation

Cite this

Rolain, T., Bernard, E., Beaussart, A., Degand, H., Courtin, P., Egge-Jacobsen, W., ... Hols, P. (2013). O-glycosylation as a novel control mechanism of peptidoglycan hydrolase activity. Journal of Biological Chemistry, 288(31), 22233-22247. https://doi.org/10.1074/jbc.M113.470716