Utilization of glycoprotein-derived N-acetylglucosamine-L-asparagine during Enterococcus faecalis infection depends on catabolic and transport enzymes of the glycosylasparaginase locus

Victor Combret; Isabelle Rincé; Aurélie Budin-Verneuil; Cécile Muller; Josef Deutscher; Axel Hartke; Nicolas Sauvageot

doi:10.1016/j.resmic.2023.104169

Utilization of glycoprotein-derived N-acetylglucosamine-L-asparagine during Enterococcus faecalis infection depends on catabolic and transport enzymes of the glycosylasparaginase locus

Res Microbiol. 2023 Nov 16:104169. doi: 10.1016/j.resmic.2023.104169. Online ahead of print.

Authors

Victor Combret¹, Isabelle Rincé¹, Aurélie Budin-Verneuil¹, Cécile Muller¹, Josef Deutscher², Axel Hartke¹, Nicolas Sauvageot³

Affiliations

¹ Normandie Université, UNICAEN, CBSA, F-14000 Caen, France.
² Université Paris Saclay, INRAE, Micalis Institute, 78350 Jouy en Josas, France; CNRS, Institut de Biologie Physico-Chimique UMR8261, Expression Génétique Microbienne, 75005 Paris, France.
³ Normandie Université, UNICAEN, CBSA, F-14000 Caen, France. Electronic address: nicolas.sauvageot@unicaen.fr.

PMID: 37977353
DOI: 10.1016/j.resmic.2023.104169

Abstract

Enterococcus faecalis is a Gram-positive clinical pathogen causing severe infections. Its survival during infection depends on its ability to utilize host-derived metabolites, such as protein-deglycosylation products. We have identified in E. faecalis OG1RF a locus (ega) involved in the catabolism of the glycoamino acid N-acetylglucosamine-L-asparagine. This locus is separated into two transcription units, genes egaRP and egaGBCD1D2, respectively. RT-qPCR experiments revealed that the expression of the ega locus is regulated by the transcriptional repressor EgaR. Electromobility shift assays evidenced that N-acetylglucosamine-L-asparagine interacts directly with the EgaR protein, which leads to the transcription of the ega genes. Growth studies with egaG, egaB and egaC mutants confirmed that the encoded proteins are necessary for N-acetylglucosamine-L-asparagine catabolism. This glycoamino acid is transported and phosphorylated by a specific phosphotransferase system EIIABC components (OG1RF_10751, EgaB, EgaC) and subsequently hydrolyzed by the glycosylasparaginase EgaG, which generates aspartate and 6-P-N-acetyl-β-d-glucosaminylamine. The latter can be used as a fermentable carbon source by E. faecalis. Moreover, Galleria mellonella larvae had a significantly higher survival rate when infected with ega mutants compared to the wild-type strain, suggesting that the loss of N-acetylglucosamine-L-asparagine utilization affects enterococcal virulence.

Keywords: Enterococcus faecalis; Glycosylasparaginase; Metabolism; N-acetylglucosamine-L-asparagine; Phosphotransferase system (PTS); ega.