Degradation of glyoxylate with ATP synthesis by a hyperthermophilic Archaeon,

Abstract

Thermococcus onnurineus NA1 is a hyperthermophilic and anaerobic euryarchaeon that is found in the deep-sea hydrothermal vent area. This organism has been known to use formate and carbon monoxide as energy sources. In this study, we show that the organism has the potential to degrade glyoxylate with ATP synthesis. Cell suspensions decompose glyoxylate yielding acetate, formate, carbon dioxide, and H2. Genome analysis could not find any gene encoding the key enzymes of the previously known pathways for glyoxylate degradation with ATP generation. Here, we propose a new pathway by genome analysis approach followed by mutation. We show that alanine:glyoxylate aminotransferase, pyruvate:ferredoxin oxidoreductase, acetyl-CoA synthetase, and 2-oxoacid:ferredoxin oxidoreductase are involved in the pathway. The results suggest that ATP is generated by substrate-level phosphorylation during glyoxylate catabolism. Analysis of a vailable genomes of the order Thermococcales or the presence of genes encoding the above enzymes suggests that the pathway seems to be limited to some species.at the organism has the potential to degrade glyoxylate with ATP synthesis. Cell suspensions decompose glyoxylate yielding acetate, formate, carbon dioxide, and H2. Genome analysis could not find any gene encoding the key enzymes of the previously known pathways for glyoxylate degradation with ATP generation. Here, we propose a new pathway by genome analysis approach followed by mutation. We show that alanine:glyoxylate aminotransferase, pyruvate:ferredoxin oxidoreductase, acetyl-CoA synthetase, and 2-oxoacid:ferredoxin oxidoreductase are involved in the pathway. The results suggest that ATP is generated by substrate-level phosphorylation during glyoxylate catabolism. Analysis of a vailable genomes of the order Thermococcales or the presence of genes encoding the above enzymes suggests that the pathway seems to be limited to some species.