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

RÍOS COLOMBO NS; SALAZAR P; CHALÓN MC; MINAHK CJ; BELLOMIO A

Córdoba

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

SAIB

p { margin-bottom: 0.25cm; line-height: 120%; }a:link { }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. coliwhen anchoredto inner membrane, independently of its specific receptor. The assayswere performed on E. coli because its lack of the receptor. In orderto prove that pore formation mechanism is not dependant of E. colimannose transporters Ecol1 y Ecol2, in this work we constructed thefusion tat?pedA under the tight control of PBAD promoter. The Tatpathway is capable of exporting heterologous proteins into theperiplasm. When Pediocin PA?1 was exported to the periplasm, it wasnot able to killE. coli. This results confirms that it does not exista specific receptor for Pediocin PA?1 in E. coli, and allow us toconclude that Ecol transporters may not be involved in EtpM?PediocinaPA?1 mechanism of action, supporting our previously developedtheory: man?PTS would act simply as an anchor and it would not beinvolved in pore formation mechanisms.