IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Brucella abortus PrrB/A: a conserved redox-responsive two-component system
Autor/es:
FERNÁNDEZ, IGNACIO; CARRICA, MARIELA DEL CARMEN; SIEIRA, RODRIGO; PARIS, GASTON; GOLDBAUM, FERNANDO
Lugar:
Mendoza
Reunión:
Congreso; XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular
Resumen:
Brucella abortus is an intracellular bacterium that needs to adapt to
an oxygen limited environment in order to achieve a successful
infection. This prompted us to search putative systems that mediate
the adaptation to the microaerobic conditions encountered by this
pathogen.
We identified in B. abortus genome the homologues to a conserved
two-component system called PrrB/A. In other microorganisms, it
has been shown that PrrB senses the redox status and, through
PrrA, generates a global response which involves expression of
high?affinity cytochrome oxidases and induction of enzymes that
allow the use of alternative electron-accepting sources.
We performed biochemical studies which indicate that
PrrB is a histidine kinase more active under reductive conditions
that phosphorylates PrrA, its cognate response regulator, as
reported in other bacteria.
We also demonstrated, using qRT?PCR, that under
microaerobiosis PrrB is necessary to achieve the induction of
high?affinity cytochrome oxidases and denitrification enzymes.
By EMSA we found that PrrA directly regulates the nitrate
reductase operon by binding to its promoter, and that
phosphorylation of PrrA increases the affinity for this DNA
fragment.
Altogether, these results show that the homologues to PrrB/A in
form a functional two-component system involved in the
adaptation to microaerobic conditions.