INVESTIGADORES
MINAHK Carlos Javier
congresos y reuniones científicas
Título:
Microcin J25 inhibits cytochrome bd oxido reductase activity
Autor/es:
GALVAN, E; CHALON, M; ACUÑA, L; SCHURIG-BRICCIO, L; MINAHK, C; GENNIS, R; BELLOMIO, A
Lugar:
Rosario
Reunión:
Congreso; L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular
Resumen:
p { margin-bottom: 0.25cm; line-height: 120%; }
Microcin J25
(MccJ25) is a plasmid -encoded antimicrobial lasso peptide
produced by Escherichia coli .
It displays antibiotic activity against a range of Gram
-negative pathogens including E. coli, Salmonella and Shigella.
MccJ25 has two cellular targets, the RNA polymerase and the
membrane respiratory chain. MccJ25 targets the respiratory
chain enzymes on the bacterial membrane with the consequent
inhibition of oxygen consumption. This effect is mediated by
an increase in superoxide production during the membrane
respiratory processes. E. coli has two terminal oxidoreductases,
the cytochrome bd and cytochrome bo3 in their respiratory system. The
E. coli C43 strain (wild type) was sensitive to the peptide whereas
the ∆bdI ∆bdII double mutant became fully resistant. In
our laboratory, cytochrome bdI was purified and the effect of MccJ25
on the activity of this terminal oxidase was studied. The ubiquinol
oxidase activity was significantly inhibited in presence of MccJ25.
This inhibition was dose dependent. Furthermore, the analysis of the
kinetic constants Km and V max allowed us to
conclude that MccJ25 would act as a non-competitive inhibitor. This
finding indicates that this lasso peptide would be capable of
inhibiting the ubiquinol activity in vitro suggesting that the
cytochrome bd might constitute a main target in E. coli membrane
chain.