INVESTIGADORES
CECCARELLI Eduardo Augusto
congresos y reuniones científicas
Título:
LepFNR es de reductant for heme degradation by Leptospira interrogans heme oxygenases
Autor/es:
SOLDANO, A; CECCARELLI, E. A.; CATALANO DUPUY, D. L.
Lugar:
Buenos Aires
Reunión:
Congreso; XLIX Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2013
Institución organizadora:
Sociedad Argentina de Investigación Bioquímica y Biología Molecular
Resumen:
Like most pathogens, Leptospira interrogans requires an iron source
for bacterial metabolism and growth during infection. Within
mammalian hosts, free iron is negligible because it is mostly bound
to high affinity proteins. However, L. interrogans has evolved to
acquire iron from host hemoglobin. A crucial protein involved in
this process is the heme oxygenase (LepHO), which cleavages the
porphyrin of heme and release iron, biliverdin and carbon monoxide.
Heme breakdown by bacterial heme oxygenases requires molecular
oxygen and an electron source derived from NADPH supplied by
ferredoxin-NADP+ reductase (FNR) and ferredoxin (Fd). The
observed Fd dependence led us to test FNR and Fd as potential
reducing partners of LepHO. Thereby, we studied the LepHO
cleavage of heme macrocycle by optical absorption spectroscopy.
We established that the plastidic-type ferredoxin-NADP+ reductase
from L. interrogans (LepFNR), acts as the physiological electron
donor without the participation of a ferredoxin. We characterized
the interaction between LepHO and LepFNR determining the
dissociation constant of LepHO-LepFNR complex. We found that
in the presence of NADPH, LepFNR and ferrozine, LepHO releases
ferrous iron. Our results indicate that LepFNR and LepHO are
involved in the heme-iron utilization pathway, through which L.
interrogans can successfully acquire iron from host for its own
survival.