Development of a suicide probe based on pediocin PA?1 that is active against Escherichia coli

RIOS COLOMBO, NS; CHALON, M; MINAHK, C; BELLOMIO, A

Mar del Plata

Congreso; LI Reunión Anual SAIB; 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Pediocin PA-1 is a subclass IIa bacteriocin produced by Pediococcus acidilactici. This group of peptides acts on the cell membrane of Gram (+) bacteria by forming pores. Apparently, these peptides bind to a membrane specific receptor. The theories on pore formation mechanism by bacteriocins suggest that they would induce conformational changes on the receptor to form a channel that remains open or, they would just use the receptor as an anchor and then form the pore. In both cases, pore formation causes leakage of ions, dissipation of proton motive force andrelease of essential metabolites. In order to study the mechanism by which Pediocin PA-1 induces the loss of membrane integrity, we led the bacteriocin to the cell membrane of E. coli, by a transcriptional fusion of the peptide with EtpM, a protein of the type II secretion system from E. coli O157: H7. In this work we constructed the fusion etpM-pedA under the tight control of PBAD promoter (repressed by glucose and induced by arabinose). In addition we carried out the co-expression of EtpM-PedA with the Pediocin PA-1 immunity protein. The results show that Pediocin PA-1 is capable of acting on Gram-negative bacteria when it is anchored in the plasmatic membrane, independently of its specific receptor. This suicidal probe will allow a deeper study of the mechanism of action ofbacteriocins and its immunity proteins, using an in vivo system.