INVESTIGADORES
CECCARELLI Eduardo Augusto
artículos
Título:
A highly stable plastidic-type ferredoxin-NADP(H) reductase in the pathogenic bacterium Leptospira interrogans
Autor/es:
CATALANO DUPUY, D. L.; MUSUMECI, M. A.; LOPEZ-RIVERO, A; CECCARELLI, E. A.
Revista:
PLOS ONE
Editorial:
PUBLIC LIBRARY SCIENCE
Referencias:
Lugar: San Francisco; Año: 2011 vol. 6 p. 26736 - 26748
ISSN:
1932-6203
Resumen:
Leptospira interrogans is a bacterium that is capable of
infecting animals and humans, and its infection causes leptospirosis
with a range of symptoms from flu-like to severe illness and death.
Despite being a bacteria, Leptospira interrogans contains a
plastidic class ferredoxin-NADP(H) reductase (FNR) with high catalytic
efficiency, at difference from the bacterial class FNRs. These
flavoenzymes catalyze the electron transfer between NADP(H) and
ferredoxins or flavodoxins. The inclusion of a plastidic FNR in Leptospira
metabolism and in its parasitic life cycle is not currently understood.
Bioinformatic analyses of the available genomic and proteins sequences
showed that the presence of this enzyme in nonphotosynthetic bacteria is
restricted to the Leptospira genus and that a [4Fe-4S] ferredoxin (LB107) encoded by the Leptospira genome may be the natural substrate of the enzyme. Leptospira
FNR (LepFNR) displayed high diaphorase activity using artificial
acceptors and functioned as a ferric reductase. LepFNR displayed
cytochrome c reductase activity with the Leptospira
LB107 ferredoxin with an optimum at pH 6.5. Structural stability
analysis demonstrates that LepFNR is one of the most stable FNRs
analyzed to date. The persistence of a native folded LepFNR structure
was detected in up to 6 M urea, a condition in which the enzyme retains
38% activity. In silico analysis indicates that the high LepFNR stability might be due to robust interactions between the FAD and the NADP+
domains of the protein. The limited bacterial distribution of plastidic
class FNRs and the biochemical and structural properties of LepFNR
emphasize the uniqueness of this enzyme in the Leptospira metabolism. Our studies show that in L. interrogans
a plastidic-type FNR exchanges electrons with a bacterial-type
ferredoxin, process which has not been previously observed in nature.