title: Unusual substrate specificity of the peptidoglycan MurE ligase from Erysipelothrix rhusiopathiae.
abstract: 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.
authors.affiliation: Institut de Biologie Intégrative de la Cellule (I2BC), UMR 9198 CEA/CNRS/Université Paris-Sud, 91405 Orsay, France. Electronic address: delphine.patin@i2bc.paris-saclay.fr.
authors.forename: Delphine
authors.initials: D
authors.lastname: Patin
authors.affiliation: Fakulteta za Farmacijo, Univerza v Ljubljani, Aškerčeva 7, 1000 Ljubljana, Slovenia.
authors.forename: Samo
authors.initials: S
authors.lastname: Turk
authors.affiliation: Institut de Biologie Intégrative de la Cellule (I2BC), UMR 9198 CEA/CNRS/Université Paris-Sud, 91405 Orsay, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Barreteau
authors.affiliation: Laboratoire de Recherche Moléculaire sur les Antibiotiques, Centre de Recherche des Cordeliers, Equipe 12, INSERM U1138, 75006 Paris, France; Université Pierre et Marie Curie - Paris 6, UMR S1138, 15 Rue de l'Ecole de Médecine, 75006 Paris, France; Université Paris-Descartes, Sorbonne Paris Cité, UMR S1138, 75006 Paris, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Mainardi
authors.affiliation: Laboratoire de Recherche Moléculaire sur les Antibiotiques, Centre de Recherche des Cordeliers, Equipe 12, INSERM U1138, 75006 Paris, France; Université Pierre et Marie Curie - Paris 6, UMR S1138, 15 Rue de l'Ecole de Médecine, 75006 Paris, France; Université Paris-Descartes, Sorbonne Paris Cité, UMR S1138, 75006 Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Arthur
authors.affiliation: Fakulteta za Farmacijo, Univerza v Ljubljani, Aškerčeva 7, 1000 Ljubljana, Slovenia.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Gobec
authors.affiliation: Institut de Biologie Intégrative de la Cellule (I2BC), UMR 9198 CEA/CNRS/Université Paris-Sud, 91405 Orsay, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Mengin-Lecreulx
authors.affiliation: Institut de Biologie Intégrative de la Cellule (I2BC), UMR 9198 CEA/CNRS/Université Paris-Sud, 91405 Orsay, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Blanot
mesh_terms: D004888:Erysipelothrix / Q000201:enzymology*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism*; D010457:Peptidoglycan / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D010457:Peptidoglycan; D010453:Peptide Synthases
keywords: Erysipelothrix rhusiopathiae; MurE; Peptidoglycan; l-alanine-adding enzyme; meso-diaminopimelate-adding enzyme