Study of the distribution of autotrophic CO2 fixation cycles in Crenarchaeota.
Two new autotrophic carbon fixation cycles have been recently described in Crenarchaeota. The 3-hydroxypropionate/4-hydroxybutyrate cycle using acetyl-coenzyme A (CoA)/propionyl-CoA carboxylase as the carboxylating enzyme has been identified for (micro)aerobic members of the Sulfolobales. The dicarboxylate/4-hydroxybutyrate cycle using oxygen-sensitive pyruvate synthase and phosphoenolpyruvate carboxylase as carboxylating enzymes has been found in members of the anaerobic Desulfurococcales and Thermoproteales. However, Sulfolobales include anaerobic and Desulfurococcales aerobic autotrophic representatives, raising the question of which of the two cycles they use. We studied the mechanisms of autotrophic CO(2) fixation in the strictly anaerobic Stygiolobus azoricus (Sulfolobales) and in the facultatively aerobic Pyrolobus fumarii (Desulfurococcales). The activities of all enzymes of the 3-hydroxypropionate/4-hydroxybutyrate cycle were found in the anaerobic S. azoricus. In contrast, the aerobic or denitrifying P. fumarii possesses all enzyme activities of the dicarboxylate/4-hydroxybutyrate cycle. We conclude that autotrophic Crenarchaeota use one of the two cycles, and that their distribution correlates with the 16S rRNA-based phylogeny of this group, rather than with the aerobic or anaerobic lifestyle.
Mikrobiologie, Fakultät Biologie, Albert-Ludwigs-Universität Freiburg, Germany.
Ivan A
IA
Berg
Mikrobiologie, Fakultät Biologie, Albert-Ludwigs-Universität Freiburg, Germany.
W Hugo
WH
Ramos-Vera
Mikrobiologie, Fakultät Biologie, Albert-Ludwigs-Universität Freiburg, Germany.
Anna
A
Petri
Lehrstuhl für Mikrobiologie und Archaeenzentrum, Universität Regensburg, Germany.
Harald
H
Huber
Mikrobiologie, Fakultät Biologie, Albert-Ludwigs-Universität Freiburg, Germany.
Georg
G
Fuchs
D052818:Autotrophic Processes; D002245:Carbon Dioxide / Q000378:metabolism*; D003998:Dicarboxylic Acids / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism; D019344:Lactic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D041523:Pyrodictiaceae / Q000201:enzymology* / Q000235:genetics; D019642:RNA, Archaeal / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D016943:Sulfolobaceae / Q000201:enzymology* / Q000235:genetics
D003998:Dicarboxylic Acids; D006885:Hydroxybutyrates; D019642:RNA, Archaeal; D012336:RNA, Ribosomal, 16S; D002245:Carbon Dioxide; C111420:4-hydroxybutyric acid; D019344:Lactic Acid; C031601:hydracrylic acid