Unusual substrate specificity of the peptidoglycan MurE ligase from Erysipelothrix rhusiopathiae. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Biochimie Année : 2016

Unusual substrate specificity of the peptidoglycan MurE ligase from Erysipelothrix rhusiopathiae.

Résumé

Erysipelothrix rhusiopathiae is a Gram-positive bacterium pathogenic to many species of birds and mammals, including humans. The main feature of its peptidoglycan is the presence of l-alanine at position 3 of the peptide stem. In the present work, we cloned the murE gene from E. rhusiopathiae and purified the corresponding protein as His6-tagged form. Enzymatic assays showed that E. rhusiopathiae MurE was indeed an l-alanine-adding enzyme. Surprisingly, it was also able, although to a lesser extent, to add meso-diaminopimelic acid, the amino acid found at position 3 in many Gram-negative bacteria, Bacilli and Mycobacteria. Sequence alignment of MurE enzymes from E. rhusiopathiae and Escherichia coli revealed that the DNPR motif that is characteristic of meso-diaminopimelate-adding enzymes was replaced by HDNR. The role of the latter motif in the interaction with l-alanine and meso-diaminopimelic acid was demonstrated by site-directed mutagenesis experiments and the construction of a homology model. The overexpression of the E. rhusiopathiae murE gene in E. coli resulted in the incorporation of l-alanine at position 3 of the peptide part of peptidoglycan.
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Dates et versions

hal-01443970 , version 1 (23-01-2017)

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Delphine Patin, Samo Turk, Hélène Barreteau, Jean-Luc Mainardi, Michel Arthur, et al.. Unusual substrate specificity of the peptidoglycan MurE ligase from Erysipelothrix rhusiopathiae.. Biochimie, 2016, 121, pp.209-18. ⟨10.1016/j.biochi.2015.12.006⟩. ⟨hal-01443970⟩
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