INVESTIGADORES
CECCARELLI Eduardo Augusto
congresos y reuniones científicas
Título:
Study of Leptospira interrogans heme oxygenase, a key enzyme in the iron acquisition
Autor/es:
SOLDANO, A; CATALANO DUPUY, D. L.; CECCARELLI, E. A.
Lugar:
Mendoza
Reunión:
Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2012
Institución organizadora:
Sociedad Argentina de Investigación Bioquímica y Biología Molecular
Resumen:
Leptospira interrogans, the pathogenic spirochete that caused
leptospirosis, acquires its essential nutrient iron from the host
hemoglobin during the infection. To scavenge the metal contained
within the heme the bacterium utilizes an enzyme known as heme
oxygenase (LepHO). Heme breakdown is a complex reaction that
requires the input of seven electrons and three molecules of oxygen
to release iron, biliverdin and carbon monoxide. Even though the
mechanism of heme cleavage is broadly conserved between HOs
from most organisms, the source of reducing equivalents is highly
variable. So far there is no evidence of which proteins support the
catalytic activity of LepHO by delivering the reducing power
needed for the acquisition of iron. We have expressed the gene
encoding LepHO and the recombinant product was purified by
affinity chromatography as a soluble protein with a molecular
weight of 26 kDa. The enzyme was able to bind its substrate heme
whit high affinity displaying a typical soret absorption peak of the
complex at 402 nm. We also studied the catalytic system of heme
degradation by optical absorption spectroscopy and we
established the physiological electron-donating partner of LepHO.
Our results suggest that the plastidic type ferredoxin-NADP
reductase found in this bacterium efficiently delivers the electrons
needed by LepHO to oxidize heme into biliverdin.