Back to Search
Start Over
Peculiar citric acid cycle of hydrothermal vent chemolithoautotroph Hydrogenovibrio crunogenus, and insights into carbon metabolism by obligate autotrophs
- Source :
- FEMS microbiology letters. 364(14)
- Publication Year :
- 2017
-
Abstract
- The genome sequence of the obligate chemolithoautotroph Hydrogenovibrio crunogenus paradoxically predicts a complete oxidative citric acid cycle (CAC). This prediction was tested by multiple approaches including whole cell carbon assimilation to verify obligate autotrophy, phylogenetic analysis of CAC enzyme sequences and enzyme assays. Hydrogenovibrio crunogenus did not assimilate any of the organic compounds provided (acetate, succinate, glucose, yeast extract, tryptone). Enzyme activities confirmed that its CAC is mostly uncoupled from the NADH pool. 2-Oxoglutarate:ferredoxin oxidoreductase activity is absent, though pyruvate:ferredoxin oxidoreductase is present, indicating that sequence-based predictions of substrate for this oxidoreductase were incorrect, and that H. crunogenus may have an incomplete CAC. Though the H. crunogenus CAC genes encode uncommon enzymes, the taxonomic distribution of their top matches suggests that they were not horizontally acquired. Comparison of H. crunogenus CAC genes to those present in other 'Proteobacteria' reveals that H. crunogenus and other obligate autotrophs lack the functional redundancy for the steps of the CAC typical for facultative autotrophs and heterotrophs, providing another possible mechanism for obligate autotrophy.
- Subjects :
- 0301 basic medicine
Chemoautotrophic Growth
Citric Acid Cycle
Heterotroph
Oxidative phosphorylation
Biology
Microbiology
03 medical and health sciences
Hydrothermal Vents
Oxidoreductase
Pyruvic Acid
Genetics
cardiovascular diseases
Autotroph
Molecular Biology
Ferredoxin
Phylogeny
chemistry.chemical_classification
Obligate
nutritional and metabolic diseases
Metabolism
Carbon
Citric acid cycle
030104 developmental biology
Glucose
chemistry
Biochemistry
Piscirickettsiaceae
Oxidation-Reduction
Subjects
Details
- ISSN :
- 15746968
- Volume :
- 364
- Issue :
- 14
- Database :
- OpenAIRE
- Journal :
- FEMS microbiology letters
- Accession number :
- edsair.doi.dedup.....8b2afcbbc9c82c072195a11d5c8a716c