Studies on the carbon monoxide dehydrogenase enzyme complex present in acetate-grown Methanosarcina thermophila strain TM-1
The carbon monoxide dehydrogenase complex was purified from acetate-grown Methanosarcina thermophila. This complex made up greater than 10% of the cellular protein and the native enzyme formed aggregates with a Mr of approximately 1,000,000. The enzyme contained five subunits of different molecular weight suggesting a multifunctional enzyme complex. The electron paramagnetic resonance spectrum of CO-reduced enzyme at 113K contained g values of 2.073, 2.049, and 2.028. Isotope substitution with {sup 61}Ni, {sup 57}Fe, or {sup 13}CO resulted in broadening of the spectrum consistent with a Ni-Fe-C spin-coupled complex. Acetyl-CoA caused a perturbation of the signal that was not caused by acetyl-phosphate or mercaptoethanol indicating acetyl-CoA is a physiological substrate. Cell extracts from acetate-grown M. thermophila contained CO-oxidizing:H{sub 2}-evolving activity 16-fold greater than extracts of methanol-grown cells. CO-oxidizing:H{sub 2}-evolving activity was reconstituted upon combination of: (i) CO dehydrogenase complex, (ii) a ferredoxin, and (iii) purified membranes with associated hydrogenase and b-type cytochrome.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA)
- OSTI ID:
- 6948586
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ACETATES
BACTERIA
CARBON 13
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CARBOXYLIC ACID SALTS
CELL CONSTITUENTS
CELL MEMBRANES
CHALCOGENIDES
CHEMICAL COMPOSITION
COMPLEXES
CULTURE MEDIA
ENZYME ACTIVITY
ENZYMES
EVEN-ODD NUCLEI
FRACTIONATION
INTERMEDIATE MASS NUCLEI
IRON 57
IRON ISOTOPES
ISOTOPES
LIGHT NUCLEI
MEMBRANES
METHANOGENIC BACTERIA
MICROORGANISMS
MOLECULAR WEIGHT
NICKEL 61
NICKEL ISOTOPES
NUCLEI
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
SEPARATION PROCESSES
STABLE ISOTOPES