Evidence for autotrophic CO2 fixation via the reductive tricarboxylic acid cycle by members of the ε subdivision of proteobacteria
Evidence for autotrophic CO2 fixation via the reductive tricarboxylic acid cycle by members of the ε subdivision of proteobacteria
Date
2005-05
Authors
Hugler, Michael
Wirsen, Carl O.
Fuchs, Georg
Taylor, Craig D.
Sievert, Stefan M.
Wirsen, Carl O.
Fuchs, Georg
Taylor, Craig D.
Sievert, Stefan M.
Linked Authors
Person
Person
Person
Person
Person
Alternative Title
Citable URI
As Published
Date Created
Location
DOI
10.1128/JB.187.9.3020-3027.2005
Related Materials
Replaces
Replaced By
Keywords
Thiomicrospira denitrificans
Candidatus Arcobacter sulfidicus
Autotrophic CO2 fixation
Candidatus Arcobacter sulfidicus
Autotrophic CO2 fixation
Abstract
Based on 16S rRNA gene surveys, bacteria of the ε subdivision of proteobacteria have been identified to be important members of microbial communities in a variety of environments, and quite a few have been demonstrated to grow autotrophically. However, no information exists on what pathway of autotrophic carbon fixation these bacteria might use. In this study, Thiomicrospira denitrificans and Candidatus Arcobacter sulfidicus, two chemolithoautotrophic sulfur oxidizers of the ε subdivision of proteobacteria, were examined for activities of the key enzymes of the known autotrophic CO2 fixation pathways. Both organisms contained activities of the key enzymes of the reductive tricarboxylic acid cycle, ATP citrate lyase, 2-oxoglutarate:ferredoxin oxidoreductase, and pyruvate:ferredoxin oxidoreductase. Furthermore, no activities of key enzymes of other CO2 fixation pathways, such as the Calvin cycle, the reductive acetyl coenzyme A pathway, and the 3-hydroxypropionate cycle, could be detected. In addition to the key enzymes, the activities of the other enzymes involved in the reductive tricarboxylic acid cycle could be measured. Sections of the genes encoding the {alpha}- and ß-subunits of ATP citrate lyase could be amplified from both organisms. These findings represent the first direct evidence for the operation of the reductive tricarboxylic acid cycle for autotrophic CO2 fixation in {varepsilon}-proteobacteria. Since {varepsilon}-proteobacteria closely related to these two organisms are important in many habitats, such as hydrothermal vents, oxic-sulfidic interfaces, or oilfields, these results suggest that autotrophic CO2 fixation via the reductive tricarboxylic acid cycle might be more important than previously considered.
Description
Author Posting. © American Society for Microbiology, 2005. This article is posted here by permission of
American Society for Microbiology for personal use, not for redistribution. The definitive version was published
in Journal of Bacteriology 187 (2005): 3020-3027, doi:10.1128/JB.187.9.3020-3027.2005.
Embargo Date
Citation
Journal of Bacteriology 187 (2005): 3020-3027