A Hydrogenosome with Pyruvate Formate-Lyase: Anaerobic Chytrid Fungi Use an Alternative Route for Pyruvate Catabolism. Mol Microbiol 32:1103-1114
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Date
1999
Journal Title
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Publisher
Wiley
Abstract
The chytrid fungi Piromyces sp. E2 and Neocallimastix
sp. L2 are obligatory amitochondriate anaerobes that
possesshydrogenosomes.Hydrogenosomes arehighly
specialized organelles engaged in anaerobic carbon
metabolism; they generate molecular hydrogen and
ATP. Here, we show for the ®rst time that chytrid
hydrogenosomes use pyruvate formate-lyase (PFL)
and not pyruvate:ferredoxin oxidoreductase (PFO) for
pyruvate catabolism, unlike all other hydrogenosomes
studied to date. Chytrid PFLs are encoded by a multigene
family and are abundantly expressed in Piromyces
sp. E2 and Neocallimastix sp. L2. Western
blotting after cellular fractionation, proteinase K protection
assays and determinations of enzyme activities
reveal that PFL is present in the hydrogenosomes of
Piromyces sp. E2. The main route of the hydrogenosomal
carbon metabolism involves PFL; the formation
of equimolar amounts of formate and acetate by isolated
hydrogenosomes excludes a signi®cant contribution
by PFO. Our data support the assumption that
chytrid hydrogenosomes are unique and argue for a
polyphyletic origin of these organelles.
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Citation
Akhmanova, A., Voncken, F.G., Hosea, K.M., Harhangi, H., Keltjens, J.T., Op Den Camp, H.J., Vogels, G.D. and Hackstein, J.H., 1999. A hydrogenosome with pyruvate formate‐lyase: Anaerobic chytrid fungi use an alternative route for pyruvate catabolism. Molecular microbiology, 32(5), pp.1103-1114.