The gelatinase biosynthesis‐activating pheromone binds and stabilises the FsrB membrane protein in Enterococcus faecalis quorum sensing

Abstract

Quorum‐sensing mechanisms regulate gene expression in response to changing cell‐population density detected through pheromones. In Enterococcus faecalis, Fsr quorum sensing produces and responds to the gelatinase biosynthesis‐activating pheromone (GBAP). Here we establish that the enterococcal FsrB membrane protein has a direct role connected with GBAP by showing that GBAP binds to purified FsrB. Far‐UV CD measurements demonstrated a predominantly α‐helical protein exhibiting a small level of conformational flexibility. Fivefold (400 μm) GBAP stabilised FsrB (80 μm) secondary structure. FsrB thermal denaturation in the presence and absence of GBAP revealed melting temperatures of 70.1 and 60.8 °C, respectively, demonstrating GBAP interactions and increased thermal stability conferred by GBAP. Addition of GBAP also resulted in tertiary structural changes, confirming GBAP binding.

Effectiveness of Bioactive Compound as Antibacterial and Anti-Quorum Sensing Agent from Myrmecodia pendans: An In Silico Study

“…PrgX, is a member of the RNPP family of regulators that controls the conjugative transfer genes expression of the E. faecalis plasmid pCF10 in response to an intercellular peptide pheromone signal [ 17 ]. Moreover, the FsrB system is an Agr-type like cyclical pheromone in E. faecalis [ 18 ], while gelatinase biosynthesis-activating pheromone (GBAP) is a pheromone in this system [ 19 , 20 ]. FsrB system encodes gelE and sprE to express gelatinase and serine protease as virulence factors.…”

Potential of MurA Enzyme and GBAP in Fsr Quorum Sensing System as Antibacterial Drugs Target: In vitro and In silico Study of Antibacterial Compounds from Myrmecodia pendans

“…Phosphorylated FsrA binds to promoters of fsrBCD and gelE-sprE [ 12 ]. Moreover, GBAP presence also makes the FsrB protein-membrane more stable [ 13 ]. Through blocking one of QS stages such as GBAP inhibition, cell-cell communication in bacteria must be ruined and finally, bacteria will be died automatically [ 14 ].…”