Studies on the Escherichia coli aerobic respiratory chain: Annual progess report, September 1, 1989--August 31, 1990
A central component of the electron transport chain which is responsible for the generation of a proton motive force is the cytochrome o terminal oxidase complex. This enzyme has been purified in our laboratory and the operon encoding the polypeptide subunits has been identified, mapped, and cloned. The project supported by this grant is to determine the structure of this enzyme in the membrane and define the mechanism of proton translocation. The cloned operon has been sequenced and the polypeptide sequence of each of the four subunits has been deduced from the DNA sequence. Three of those subunits are strikingly homologous to corresponding subunits in the mitochondrial cytochrome c oxidase, an enzyme that has been very extensively studied. Subunit I, the largest, is identical in 40% of the amino acid residues to the corresponding subunit in bovine cytochrome c oxidase. Biophysical studies have confirmed this unexpected finding, that the bacterial quinol oxidase (cytochrome o) is structually similar to the eukaryotic cytochrome c oxidases. Various mutations will be made to identify the role of each subunit within the complex. One focus will be to identify amino acid residues involved in ubiquinol binding. Work has been initiated on another enzyme, succinate dehydrogenase, which also interacts with ubiquinone. A similar molecular genetics approach will be used to define the quinone binding site in this enzyme and search for similarities with the quinone binding site in the cytochrome o complex.
- Research Organization:
- Illinois Univ., Urbana (USA)
- DOE Contract Number:
- FG02-87ER13716
- OSTI ID:
- 6256177
- Report Number(s):
- DOE/ER/13716-1; ON: DE89011418
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ESCHERICHIA COLI
CYTOCHROMES
BENZOQUINONES
PHOSPHORYLATION
PROGRESS REPORT
AROMATICS
BACTERIA
CHEMICAL REACTIONS
DOCUMENT TYPES
MICROORGANISMS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PIGMENTS
PROTEINS
QUINONES
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)