Use of TAT-dependant system to study pediocin PA-1 mechanism of action against E. coli

RIOS COLOMBO, NS; SALAZAR PB; CHALON MC; MINAHK C; BELLOMIO A

Córdoba

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

The bacteriocinPediocin PA?1 belongs to a group of peptides active onGram?positive bacteria membrane. They bind to a specific receptor,the mannose phosphotransferase system (man?PTS) that is believed toparticipate in the formation of a pore. In standard conditions thesebacteriocins are not active against Gram?negative bacteria whenadded to culture medium. Previously in our laboratory, wedemonstrated that the intracellular expression of the fusionetpm?pedA induces loss of membrane integrity on E. coli whenanchored to inner membrane, independently of its specific receptor.The assays were performed on E. coli because its lack of thereceptor. In order to prove that pore formation mechanism is notdependant of E. coli mannose transporters Ecol1 y Ecol2, in this workwe constructed the fusion tat?pedA under the tight control of PBADpromoter. The Tat pathway is capable of exporting heterologousproteins into the periplasm. When Pediocin PA?1 was exported to theperiplasm, it was not able to kill E. coli. This results confirmsthat it does not exist a specific receptor for Pediocin PA?1 in E.coli, and allow us to conclude that Ecol transporters may not beinvolved in EtpM?Pediocina PA?1 mechanism of action, supportingour previously developed theory: man?PTS would act simply as ananchor and it would not be involved in pore formation mechanisms.p { margin-bottom: 0.25cm; line-height: 115%; }