Analysis of the Streptococcus agalactiae exoproteome

Salvatore Papasergi (1) , Roberta Galbo (2) , Veronica Lanza-Cariccio (1) , Maria Domina (1) , Giacomo Signorino (1) , Carmelo Biondo (1) , Ida Pernice (2) , Claire Poyart (3) , Patrick Trieu-Cuot (4) , Giuseppe Teti (1) , Concetta Beninati (1)

1 Elie Metchnikoff Laboratory
2 Dipartimento di Scienze Biologiche e Ambientali
3 Service de Bactériologie
4 Biologie des Bactéries pathogènes à Gram-positif

The two-component regulatory system CovRS is the main regulator of virulence gene expression in Group B Streptococcus (GBS), the leading cause of invasive infections in neonates. In this study we analyzed by mass spectrometry the GBS extracellular protein complex (i.e. the exoproteome) of NEM316 wild-type (WT) strain and its isogenic covRS deletion mutant (ΔcovRS). A total of 53 proteins, 49 of which had classical secretion signals, were identified: 12 were released by both strains while 21 and 20 were released exclusively by WT and ΔcovRS strains, respectively. In addition to known surface proteins, we detected here unstudied cell-wall associated proteins and/or orthologs of putative virulence factors present in other pathogenic streptococci. While the functional role of these proteins remains to be elucidated, our data suggest that the analysis of the exoproteome of bacterial pathogens under different gene expression conditions may be a powerful tool for the rapid identification of novel virulence factors and vaccine candidates.

Mots clés: Bacterial infections; Mass spectrometry; Proteomics; Virulence factors

Domaines: Bactériologie

Salvatore Papasergi, Roberta Galbo, Veronica Lanza-Cariccio, Maria Domina, Giacomo Signorino, et al.. Analysis of the Streptococcus agalactiae exoproteome. Journal of Proteomics, 2013, 89, pp.154-164. ⟨10.1016/j.jprot.2013.06.003⟩. ⟨pasteur-01300162⟩