Study of a protease inhibitor and its role in oral Brucella abortus infection

CARABAJAL, MARIANELA; PASQUEVICH, KARINA; REY SERRANTES, DIEGO; COMERCI, DIEGO; CASSATARO, JULIANA

Mar del Plata

Congreso; LI Reunión Annual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Brucellosis is a world widespread zoonotic disease. Oral infection is one of the ways in which the disease is acquired.Previous results demonstrated that a purified recombinant Brucella spp. protein called U-Omp19 is able to inhibit in vitro the activity of main gastrointestinal proteases. In this work, we performed kinetic assays using trypsin-, α-chymotrypsin- and pancreatic elastase-specific substrates and demonstrated that U-Omp19 inhibits the three serin proteases by a mixed noncompetitive mechanism with Ki values in the μM range. To test if Omp19 in the Brucella membrane protects it against the bactericidal activity of the main gut proteases, an Omp19-deficient strain (Δomp19 Ba) and the complemented mutant (Δomp19-omp19 Ba) were generated. In contrast to WT Ba, Δomp19 Ba was susceptible to elastase bactericidal activity (P