Mitochondrial H+-ATPase in mutants of saccharomyces cerevisiae with defective subunit 8 of the enzyme complex
| Autor: | Sangkot Marzuki, Wan M. Choo, Linton C. Watkins |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
Enzyme complex
Oligomycin Macromolecular Substances Protein subunit ATPase Molecular Sequence Data Mutant Saccharomyces cerevisiae Biophysics Mitochondrion Biochemistry chemistry.chemical_compound Oxygen Consumption ATP synthase gamma subunit Amino Acid Sequence biology Cell Biology Models Theoretical biology.organism_classification Molecular biology Mitochondria Kinetics Proton-Translocating ATPases chemistry Protein Biosynthesis Mutation biology.protein |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Bioenergetics. 975:222-230 |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/s0005-2728(89)80252-x |
| Popis: | Mutants of Saccharomyces cerevisiae carrying defined lesions in the mitochondria! aapl gene, coding for membrane subunit 8 of the H + - ATPase, have been investigated to examine the consequence of the mutations on the function and assembly of the enzyme complex. These include three mit − mutants, which cannot grow by oxidative metabolism due to their inability to synthesize full-length subunit 8, and three partial revertants of one of the mutants. The mutations in these strains have been previously characterized by DNA sequencing. The use of a monoclonal antibody to the β subunit of the H + -ATPase as a probe of assembly defect revealed that the presence of subunit 8 is essential for the assembly of subunit 6 to the enzyme complex. Mitochondria isolated from the mit − mutants have negligible [ 32 P i ]ATP exchange activity and they exhibited ATPase activity which is not sensitive to inhibition by oligomycin, indicating a defective membrane F 0 sector. Normal assembly of subunit 8 (and subunit 6) was observed in the revertant strains, despite 8-9 amino-acid substitutions in the membrane- spanning region of the H + -ATPase subunit 8 in two of the strains. The assembled complex, however, exhibited reduced [ 32 P i ]JATP exchange activity and low sensitivity to oligomycin, indicating that the product of the aapl gene is a functional subunit of the mitochondrial H + -ATPase. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|