The Polyamine N-Acetyltransferase-Like Enzyme PmvE Plays a Role in the Virulence of Enterococcus faecalis

ABSTRACTWe previously showed that the mutant strain of Enterococcus faecalislacking the transcriptional regulator SlyA is more virulent than the parental strain. We hypothesized that this phenotype was due to overexpression of the second gene of the slyAoperon, ef_3001, renamed pmvE(for polyamine metabolism and virulence of E. faecalis). PmvE shares strong homologies with N1-spermidine/spermine acetyltransferase enzymes involved in the metabolism of polyamines. In this study, we used an E. faecalisstrain carrying the recombinant plasmid pMSP3535-pmvE(V19/p3535-pmvE), which allows the induction of pmvEby addition of nisin. Thereby, we showed that the overexpression of PmvE increased the virulence of E. faecalisin the Galleria mellonellainfection model, as well as the persistence within peritoneal macrophages. We were also able to show a direct interaction between the His-tagged recombinant PmvE (rPmvE) protein and putrescine by the surface plasmon resonance (SPR) technique on a Biacore instrument. Moreover, biochemical assays showed that PmvE possesses an N-acetyltransferase activity toward polyamine substrates. Our results suggest that PmvE contributes to the virulence of E. faecalis, likely through its involvement in the polyamine metabolism.