Enzymological studies of one-carbon reactions in the pathway of acetate utilization by methanogenic bacteria
Several enzymes in the pathway of acetate conversion to methane and carbon dioxide have been purified from Methanosarcina thermophila. The mechanisms of these enzymes are under investigation utilizing biochemical, biophysical and molecular genetic approaches. Acetate kinase and phosphotransacetylase catalyzes the activation of acetate to acetyl-CoA. The primary structure of these enzymes will be determined through cloning and sequencing of the genes. Two protein components of the CO dehydrogenase complex are under investigations. The metal centers of each component have been characterized using EPR. Cloning and sequencing of the genes for the two subunits of each component is in progress. Results indicate that the Ni/Fe-S component cleaves the C-C and C-S bonds of acetyl-CoA followed by oxidation of the carbonyl group to carbon dioxide and transfer of the methyl group to the Co/Fe-S component. The enzymes and cofactors involved in transfer of the methyl group from the Co/Fe-S component to coenzyme M will be purified and characterized. Ferredoxin is an electron acceptor for the Ni/Fe-S component and also serves to reductively reactivate methylreductase which catalyzes the demethylation of methyl coenzyme M to methane. This ferredoxin is being characterized utilizing EPR and RR spectroscopic methods to determine the properties of the Fe-S centers. Genes encoding this and other ferredoxins have been cloned and sequenced to determine the primary structures. Carbonic anhydrase is being purified and characterized to determine the function of this enzyme in the pathway.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Anaerobic Microbiology
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG05-87ER13730
- OSTI ID:
- 5489407
- Report Number(s):
- DOE/ER/13730-T1; ON: DE92010313
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COBALT
CHEMICAL REACTIONS
COMPLEXES
FERREDOXIN
SPECTROSCOPY
IRON COMPLEXES
METHANOGENIC BACTERIA
BIOCHEMISTRY
NICKEL
ACETATES
CARBON DIOXIDE
CHEMICAL BONDS
CLONING
ENZYME ACTIVITY
METHANE
OXIDOREDUCTASES
PHOSPHOTRANSFERASES
ALKANES
BACTERIA
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CHEMISTRY
ELEMENTS
ENZYMES
HYDROCARBONS
METALLOPROTEINS
METALS
MICROORGANISMS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PROTEINS
TRANSFERASES
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENTS
550200* - Biochemistry
550700 - Microbiology