Editor: Elizabeth Baggs
Carbon dioxide fixation in ‘Archaeoglobus lithotrophicus’: are there multiple autotrophic pathways?
Article first published online: 4 APR 2011
© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Microbiology Letters
Volume 319, Issue 1, pages 65–72, June 2011
How to Cite
Estelmann, S., Ramos-Vera, W. H., Gad'on, N., Huber, H., Berg, I. A. and Fuchs, G. (2011), Carbon dioxide fixation in ‘Archaeoglobus lithotrophicus’: are there multiple autotrophic pathways?. FEMS Microbiology Letters, 319: 65–72. doi: 10.1111/j.1574-6968.2011.02268.x
- Issue published online: 21 APR 2011
- Article first published online: 4 APR 2011
- Accepted manuscript online: 15 MAR 2011 10:05AM EST
- Received 27 January 2011; revised 8 March 2011; accepted 11 March 2011., Final version published online 4 April 2011.
- Archaeoglobus lithotrophicus;
- 4-hydroxybutyryl-CoA dehydratase;
- dicarboxylate/hydroxybutyrate cycle;
- hydroxypropionate/hydroxybutyrate cycle;
- ribulose 1,5-bisphosphate carboxylase
Several representatives of the euryarchaeal class Archaeoglobi are able to grow facultative autotrophically using the reductive acetyl-CoA pathway, with ‘Archaeoglobus lithotrophicus’ being an obligate autotroph. However, genome sequencing revealed that some species harbor genes for key enzymes of other autotrophic pathways, i.e. 4-hydroxybutyryl-CoA dehydratase of the dicarboxylate/hydroxybutyrate cycle and the hydroxypropionate/hydroxybutyrate cycle and ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) of the Calvin–Benson cycle. This raised the question of whether only one or multiple autotrophic pathways are operating in these species. We searched for the presence of enzyme activities specific for the dicarboxylate/hydroxybutyrate or the hydroxypropionate/hydroxybutyrate cycles in ‘A. lithotrophicus’, but such enzymes could not be detected. Low Rubisco activity was detected that could not account for the carbon dioxide (CO2) fixation rate; in addition, phosphoribulokinase activity was not found. The generation of ribulose 1,5-bisphosphate from 5-phospho-d-ribose 1-pyrophosphate was observed, but not from AMP; these sources for ribulose 1,5-bisphosphate have been proposed before. Our data indicate that the reductive acetyl-CoA pathway is the only functioning CO2 fixation pathway in ‘A. lithotrophicus’.