Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete nucleotide sequence of the circular mitochondrial (mt) DNA from the red alga Chondrus crispus was determined (25,836 nucleotides, A+T content 72.1%). Fifty one genes were identified. They include genes encoding three subunits of the cytochrome oxidase (cox1 to 3), apocytochrome b (cob), seven subunits of the NADH dehydrogenase complex (nad1 to 6, nad4L), two ATPase subunits (atp6 and atp9), three ribosomal RNAs (rrn5, srn and lrn), 23 tRNAs and four ribosomal proteins (rps3, rps11, rps12 and rpl16). Two subunits of the succinate dehydrogenase complex (sdhB and sdhC), usually found on nuclear genomes, are also located on the mtDNA of C. crispus. One group IIb intron is inserted in the tRNAIle gene. Six potentially functional open reading frames were identified, four of them having counterparts among green plant mtDNAs. The use of a modified genetic code and the absence of RNA editing, previously reported for the cox3 gene, appears as a general characteristic of this molecule. Mitochondrial genes are encoded on both DNA strands, in two opposite major transcriptional directions, suggesting the existence of two main transcriptional units. Two long and stable stem-loops were identified in intergenic regions, which are believed to be involved with transcription and replication. The main structural features of this genome are compared with the overall organization of mtDNAs and are discussed in view of the evolution of mitochondria.
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PMID:Complete sequence of the mitochondrial DNA of the rhodophyte Chondrus crispus (Gigartinales). Gene content and genome organization. 761 69

The availability of the complete sequence of a genome allows a systematic analysis of its expression. Gene-specific variations of transcription levels and phenomena such as transcript processing and RNA editing require large numbers of clones to be examined. For the completely sequenced mitochondrial genome of Arabidopsis thaliana we adapted robot technology to identify and characterize expressed genes. A cDNA library of about 50,000 clones was constructed, robot-ordered into 384-well microtitre plates and spotted onto high-density filter membranes. These filters permit the isolation of large numbers of specific cDNA clones in a single hybridization step. The cox1, cox2 and cox3 genes were used to evaluate the feasibility and efficiency of this approach. A cluster of RNA editing sites observed outside the cox3 coding region identifies a novel reading frame orf95 in higher plants with significant similarity to a subunit of respiratory chain complex II.
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PMID:An ordered Arabidopsis thaliana mitochondrial cDNA library on high-density filters allows rapid systematic analysis of plant gene expression: a pilot study. 977 52

We describe here a new type of mitochondrial mutation (dum24; for dark uniparental minus inheritance) of the unicellular photosynthetic alga Chlamydomonas reinhardtii. The mutant fails to grow under heterotrophic conditions and displays reduced growth under both photoautotrophic and mixotrophic conditions. In reciprocal crosses between mutant and wild-type cells, the meiotic progeny only inherit the phenotype of the mating-type minus parent, indicating that the dum24 mutation exclusively affects the mitochondrial genome. Digestion with various restriction enzymes followed by DNA gel blot hybridizations with specific probes demonstrated that dum24 cells contain four types of altered mitochondrial genomes: deleted monomers lacking cob, nd4, and the 3' end of the nd5 gene; deleted monomers deprived of cob, nd4, nd5, and the 5' end of the cox1 coding sequence; and two types of dimers produced by end-to-end fusions between monomers similarly or differently deleted. Due to these mitochondrial DNA alterations, complex I activity, the cytochrome pathway of respiration, and presumably, the three phosphorylation sites associated with these enzyme activities are lacking in the mutant. The low respiratory rate of the dum24 cells results from the activities of rotenone-resistant NADH dehydrogenase, complex II, and alternative oxidase, with none of these enzymes being coupled to ATP production. To our knowledge, this type of mitochondrial mutation has never been described for photosynthetic organisms or more generally for obligate aerobes.
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PMID:Alteration of dark respiration and reduction of phototrophic growth in a mitochondrial DNA deletion mutant of Chlamydomonas lacking cob, nd4, and the 3' end of nd5. 987 36

Two substitutions A1090G and A1098C (together called the m mutation) located in the conserved GTPase domain of the mitochondrial LSU rRNA gene were recently shown to weakly compensate for the phenotypical effect of a -1T frameshift mutation in the mitochondrial cox1 gene of C. reinhardtii. In order to analyze the impact of the m mutation on the mitochondrial translational machinery, a strain carrying the m mutation but wild-type for the cox1 gene was isolated. We found that the growth and the respiratory rate of the m mutant were affected and that the activities of complexes I, III, and IV, all containing mitochondria-encoded subunits, were lowered. In contrast the activities of complex II and of the alternative oxidase, both encoded exclusively by the nuclear genome, were not modified. The steady-state levels of complex I enzyme and of several components of the respiratory complexes I, III, and IV were also reduced in the mutant. We moreover showed that m did not suppress other frameshift or UGA stop mutations which affect mitochondrial genes.
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PMID:Impact of a mutation in the mitochondrial LSU rRNA gene from Chlamydomonas reinhardtii on the activity and the assembly of respiratory-chain complexes. 1501 77