Lack of mitochondrial and nuclear-encoded subunits of complex I and alteration of the respiratory chain in Nicotiana sylvestris mitochondrial deletion mutants
| Autor: | Hervé Degand, Fernand Vedel, Sophie Gutierres, Christine Lelandais, P. Chetrit, Rosine De Paepe, Mohammed Sabar, Philippe Diolez, Yaroslav de Kouchkovsky, Marc Boutry |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Alternative oxidase
Mitochondrial DNA Protein subunit Molecular Sequence Data Respiratory chain Glycine Biology Mitochondrion Electron Transport Tobacco NAD(P)H Dehydrogenase (Quinone) Amino Acid Sequence Sequence Deletion Genetics Cell Nucleus Multidisciplinary Sequence Homology Amino Acid Wild type Biological Sciences biology.organism_classification Mitochondria Oxygen Plants Toxic Mitochondrial respiratory chain Biochemistry Mutation Nicotiana sylvestris |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America. 94(7) |
| ISSN: | 0027-8424 |
| Popis: | We previously have shown that Nicotiana sylvestris cytoplasmic male sterile (CMS) mutants I and II present large mtDNA deletions and that the NAD7 subunit of complex I (the main dehydrogenase of the mitochondrial respiratory chain) is absent in CMS I. Here, we show that, despite a large difference in size in the mtDNA deletion, CMS I and II display similar alterations. Both have an impaired development from germination to flowering, with partial male sterility that becomes complete under low light. Besides NAD7, two other complex I subunits are missing (NAD9 and the nucleus-encoded, 38-kDa subunit), identified on two-dimensional patterns of mitochondrial proteins. Mitochondria isolated from CMS leaves showed altered respiration. Although their succinate oxidation through complex II was close to that of the wild type, oxidation of glycine, a priority substrate of plant mitochondria, was significantly reduced. The remaining activity was much less sensitive to rotenone, indicating the breakdown of Complex I activity. Oxidation of exogenous NADH (coupled to proton gradient generation and partly sensitive to rotenone) was strongly increased. These results suggest respiratory compensation mechanisms involving additional NADH dehydrogenases to complex I. Finally, the capacity of the cyanide-resistant alternative oxidase pathway was enhanced in CMS, and higher amounts of enzyme were evidenced by immunodetection. |
| Databáze: | OpenAIRE |
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