Record number | 442283 |
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Title | O-glycosylation as a novel control mechanism of peptidoglycan hydrolase activity |
Author(s) | Rolain, T.; Bernard, E.; Beaussart, A.; Degand, H.; Courtin, P.; Egge-Jacobsen, W.; Bron, P.A.; Morsomme, P.; Kleerebezem, M.; Chapot-Chartier, M.P.; Dufrêne, Y.F.; Hols, P. |
Source | Journal of Biological Chemistry 288 (2013)31. - ISSN 0021-9258 - p. 22233 - 22247. |
DOI | http://dx.doi.org/10.1074/jbc.M113.470716 |
Department(s) |
Host Microbe Interactomics WIAS |
Publication type | Refereed Article in a scientific journal |
Publication year | 2013 |
Keyword(s) | lactobacillus-plantarum wcfs1 - diamino acid endopeptidase - lactococcus-lactis - teichoic-acids - staphylococcus-aureus - cell-separation - bacterial-peptidoglycan - n-acetylglucosaminidase - listeria-monocytogenes - protein glycosylation |
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. |
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