Use of a Tat-dependant system to study Pediocin PA-1 mechanism of action against E. coli

RIOS COLOMBO, N.S.; SALAZAR, P.B.; CHALON M.C.; MINAHK, C.J; BELLOMÍO A

Cordoba

Congreso; Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2016

Sociedad Argentina de Investigaciones en Bioquimica y Biologia Molecular

The bacteriocin Pediocin PA-1 belongs to a group of peptides active on Gram (+) bacteria membrane. They bind to a specific receptor, the mannose phosphotransferase system (man-PTS) that is believed to participate in the formation of a pore. In standard conditions these bacteriocins are not active against Gram-negative bacteria when added to culture medium. Previously in our laboratory, we demonstrated that the intracellular expression of the fusion etpm-pedA, induces loss of membrane integrity on E. coli when anchored to inner membrane, independently of its specific receptor. The assays were performed on E. coli because its lack of the receptor. In order to prove that pore formation mechanism is not dependant of E. coli mannose transporters Ecol1 y Ecol2, in this work we constructed the fusion tat-pedA under the tight control of PBAD promoter. The Tat pathway is capable of exporting heterologous proteins into the periplasm. When Pediocin PA-1 was exported to the periplasm, it was not able to kill E. coli. This results confirms that it does not exist a specific receptor for Pediocin PA-1 in E. coli, and allow us to conclude that Ecol transporters may not be involved in EtpM-Pediocina PA-1 mechanism of action, supporting our previously developed theory: man-PTS would act simply as an anchor and it would not be involved in pore formation mechanisms.