A Hydrogenosome with Pyruvate Formate-Lyase: Anaerobic Chytrid Fungi Use an Alternative Route for Pyruvate Catabolism. Mol Microbiol 32:1103-1114

Akhmanova, Anna; Voncken, Frank; Hosea, Ken M.; Harhangi, H.; Keltjens, J. T.; Op Den Camp, H. J.; Vogels, G. D.; Hackstein, Johannes H. P.

A Hydrogenosome with Pyruvate Formate-Lyase: Anaerobic Chytrid Fungi Use an Alternative Route for Pyruvate Catabolism. Mol Microbiol 32:1103-1114

Authors

Hackstein, Johannes H. P.

Publisher

Wiley

Description

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.