Details

Autor(en) / Beteiligte

• Rolain, Thomas
• Bernard, Elvis
• Beaussart, Audrey
• Degand, Hervé
• Courtin, Pascal
• Egge-Jacobsen, Wolfgang
• Bron, Peter A.
• Morsomme, Pierre
• Kleerebezem, Michiel
• Chapot-Chartier, Marie-Pierre
• Dufrêne, Yves F.
• Hols, Pascal

Titel

O-Glycosylation as a Novel Control Mechanism of Peptidoglycan Hydrolase Activity

Ist Teil von

• The Journal of biological chemistry, 2013-08, Vol.288 (31), p.22233-22247

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2013

Quelle

EZB-FREE-00999 freely available EZB journals

Beschreibungen/Notizen

• 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. Background: A range of peptidoglycan hydrolases (PGHs) contain low complexity domains of unknown function. Results:O-Glycosylation of the low complexity domain of the Lactobacillus plantarum autolysin Acm2 is a major negative modulator of enzymatic activity. Conclusion:O-Glycosylation represents an autoregulatory control mechanism of PGH activity. Significance: This is the first functional evidence that glycosylation controls the activity of a bacterial enzyme.