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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)

A reverse-phase HPLC System for isolation of the water insoluble alpha- and beta-polypeptides of the light-harvesting complex II (LH II) of Rhodopseudomonas (Rps.) palustris without employment of any detergent was developed. The material obtained was of high purity and suitable for direct microsequence analysis. Chromatographic analysis could resolve at least two major beta-polypeptides, beta a and beta b, two major alpha-polypeptides, alpha a and alpha b, and two additional minor polypeptides. N-terminal amino acid sequencing shows that the resolved peaks correspond to different polypeptide species and that the minor species have an N-terminal sequence identical to that of the alpha b polypeptide. An oligonucleotide derived from the amino terminal sequence of the alpha a polypeptide was utilized to screen a genomic library from Rps.palustris. Several independent clones have been characterized by Southern blot and nucleotide sequence analysis. We show that Rps.palustris contains at least four different clusters of beta and alpha genes. Two clones contain sequences potentially coding for beta a-alpha a and beta b-alpha b polypeptides; and two additional clones potentially coding for beta and alpha peptides which we named beta c-alpha c and beta d-alpha d, which did not correspond to the major purified polypeptides. In addition to the protein chemistry data, the conservation at the amino acid level and the presence of canonical ribosomal binding sites upstream of each of the identified genes strongly suggest that all four coding regions are expressed.
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PMID:Multiple copies of the coding regions for the light-harvesting B800-850 alpha- and beta-polypeptides are present in the Rhodopseudomonas palustris genome. 267 May 51

Membrane-bound succinate oxidoreductases are flavoenzymes containing one each of a 2Fe, a 3Fe and a 4Fe iron-sulfur center. Amino acid sequence homologies indicate that all three centers are located in the Ip (B) subunit. From polypeptide and gene analysis of Bacillus subtilis succinate dehydrogenase-defective mutants combined with earlier EPR spectroscopic data, we show that four conserved cysteine residues in the first half of Ip are the ligands to the [2Fe-2S] center. These four residues have previously been predicted to be the ligands. Our results also suggest that the N-terminal part of B. subtilis Ip constitutes a domain which can incorporate separately the 2Fe center and interact with Fp, the flavin-containing subunit of the dehydrogenase.
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PMID:Ligands to the 2Fe iron-sulfur center in succinate dehydrogenase. 283 11

In a previous report, mitochondria were proposed as a subcellular structure where recognition sites for peripheral benzodiazepine ligands are located in adrenal glands. The present study examines the subcellular distribution of specific binding sites for PK 11195 in eight tissues and compares the relative densities of these binding sites in mitochondrial-enriched fractions with the relative activities of two mitochondrial marker enzymes. In all eight tissues examined, PK 11195 binding sites were found to subfractionate in a manner nearly identical to that of the mitochondrial enzyme succinate dehydrogenase. The subcellular distribution patterns of specific PK 11195 binding sites were unrelated to the distribution patterns of marker enzymes for plasma membranes, lysosomes, or endoplasmic reticulum. Scatchard analyses of mitochondrial fractions from all eight tissues demonstrated a greater than 100-fold difference in the densities of PK 11195 binding sites, the extremes being 140 and 1 pmol/mg of protein in adrenal and brain tissues, respectively. There was no correlation between the relative density of PK 11195 binding sites and the specific activities of succinate dehydrogenase and cytochrome c oxidase. These results suggest that the density of peripheral-type benzodiazepine receptors in mitochondria is tissue dependent and apparently regulated independently of the mechanisms by which these two mitochondrial enzymes are expressed or function. The photoaffinity probe PK 14105 was used to photolabel the peripheral-type benzodiazepine binding sites of mitochondrial fractions prepared from the eight tissues. In all preparations, a 17,000-Da polypeptide is specifically labeled as determined by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. Thus, it appears that the protein recognition site for isoquinoline carboxamides of peripheral-type benzodiazepine receptor complexes is similar in all mitochondrial preparations.
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PMID:Molecular characterization and mitochondrial density of a recognition site for peripheral-type benzodiazepine ligands. 284 47

Succinate dehydrogenase is a conserved membrane-bound enzyme consisting of two nonidentical subunits: a flavo iron-sulfur protein (Fp) subunit, containing a covalently bound flavin, and an iron-sulfur protein (Ip) subunit. Bacillus subtilis succinate dehydrogenase in wild type bacteria and 12 well characterized succinate dehydrogenase-defective mutants were examined by low temperature EPR spectroscopy to characterize the enzyme and study subunit location and biosynthesis of its iron-sulfur clusters. The wild type B. subtilis enzyme contains iron-sulfur clusters which are analogous to clusters S-1 and S-3 of bovine heart succinate dehydrogenase but with slightly different EPR characteristics. Spins from cluster S-2 were not detectable as in the case of the intact form of bovine heart succinate dehydrogenase. However, dithionite reduction of the B. subtilis enzyme greatly enhanced spin relaxation of the ferredoxin-type cluster S-1, indicating the presence of the cluster S-2. Iron-sulfur cluster S-1 was found to be assembled in soluble succinate dehydrogenase subunits in the cytoplasm, but only if full-length Fp polypeptides and relatively large fragments of Ip polypeptides were present. Cluster S-1 was not detected in mutants with soluble mutated Fp polypeptides or in a mutant totally lacking Ip subunit polypeptide. Iron-sulfur clusters S-1, S-2, and S-3 were assembled also when the covalently bound flavin in the Fp subunit was absent. Clusters S-1 and S-3 in the membrane-bound flavin-deficient succinate dehydrogenase were not reduced by succinate but could be reduced by electron transfer from NADH dehydrogenase via the menaquinone pool.
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PMID:Characterization by electron paramagnetic resonance and studies on subunit location and assembly of the iron-sulfur clusters of Bacillus subtilis succinate dehydrogenase. 298 99

The primary structure of the succinyl-CoA synthetase of Escherichia coli has been deduced from the nucleotide sequence of a 2451-base-pair segment of DNA containing the corresponding sucC (beta subunit) and sucD (alpha subunit) genes. The genes are located at one end of a gene cluster that encodes several citric acid cycle enzymes: gltA-sdhCDAB-sucABCD; gltA, citrate synthase; sdh, succinate dehydrogenase; sucA and sucB, the dehydrogenase (E1) and succinyltransferase (E2) components of the 2-oxoglutarate dehydrogenase complex. The sucC and sucD genes are separated from the sucA and sucB genes by a 273-base-pair segment containing four palindromic units, but they appear to be expressed from a sucABCD read-through transcript that extends from the suc promoter to a potential rho-independent terminator at the distal end of sucD. The stop codon of the sucC gene overlaps the sucD initiation codon by a single nucleotide, indicating close translational coupling of the sucC and sucD genes. The sucC gene comprises 1161 base pairs (388 codons, excluding the stop codon), and it encodes a polypeptide of Mr 41 390 corresponding to the beta subunit of succinyl-CoA synthetase. The sucD gene comprises 864 base pairs (288 codons, excluding the start and stop codons), and it encodes a product of Mr 29 644, corresponding to the alpha subunit of succinyl-CoA synthetase. The alpha subunit contains a 12-residue amino acid sequence that is identical with the histidine peptide previously isolated from the phosphoenzyme. This sequence forms part of one of the two potential nucleotide binding sites detected in the alpha subunit.
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PMID:Primary structure of the succinyl-CoA synthetase of Escherichia coli. 300 35

Mitochondria isolated from the skeletal muscle of an infant with mitochondrial myopathy and renal dysfunction were analyzed. Activities of NADH dehydrogenase, succinate dehydrogenase, ubiquinol-cytochrome c oxidoreductase, and cytochrome c oxidase were severely decreased. Cytochromes aa3 and b were not detected in patient mitochondria, and the cytochrome c+c1 content was 14% of control. Immunoblotting demonstrated that the amount of cytochrome c oxidase subunits were markedly decreased in patient mitochondria. The polypeptide profile of patient mitochondria was quite different from that of control mitochondria. These results suggest that deterioration of mitochondria in a severe case of mitochondrial myopathy involves not only cytochrome c oxidase but also other mitochondrial proteins.
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PMID:Multiple cytochrome deficiency and deteriorated mitochondrial polypeptide composition in fatal infantile mitochondrial myopathy and renal dysfunction. 301 32

A method has been developed for purification of highly active ubiquinol-cytochrome c oxidoreductase (cytochrome bc1) complexes from wild-type Rhodobacter sphaeroides, Rhodobacter capsulatus MT1131, bovine heart and yeast mitochondria. This is the first report of the isolation of cytochrome bc1 complex from a wild-type strain of Rb. sphaeroides and from any strain of Rb. capsulatus. The purification involves extraction of membranes with dodecyl maltoside and two successive DEAE column chromatography steps. All of the resulting bc1 complexes are free of succinate dehydrogenase and cytochrome c oxidase activities. The purified bc1 complexes from both photosynthetic bacteria contain four polypeptide subunits, although the molecular weights of some of their subunits differ. They are also free of reaction center and light-harvesting pigments and polypeptides. The turnover number of the Rb. sphaeroides complex is 128 s-1, and that of the Rb. capsulatus complex is 64 s-1. The bc1 complex from bovine heart contains eight polypeptides and has a turnover number of 1152 s-1, while the yeast complex contains nine polypeptides and has a turnover number of 219 s-1. The activities of these complexes are equal to or better than those commonly obtained by previously reported methods. This method of purification is relatively simple, reproducible, and yields cytochrome bc1 complexes which largely retain the turnover number of the starting material and are pure on the basis of optical spectra, enzymatic activities and polypeptide composition. The purification of cytochrome bc1 complexes from energy-transducing membranes which differ markedly in their lipid and protein composition makes it likely that with minor modifications this method could be applied to species other than those described here.
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PMID:Purification of highly active cytochrome bc1 complexes from phylogenetically diverse species by a single chromatographic procedure. 303 52

The damaging effects of ADP/Fe/NADPH-induced lipid peroxidation were studied on the enzymes and membranes of rat liver mitochondria. Succinate, an inhibitor of mitochondrial lipid peroxidation, prevented or delayed most of the damage caused by the peroxidation on different mitochondrial structures and functions. There were marked abnormalities on the electrophoretic pattern of mitochondrial proteins during the course of lipid peroxidation. The disappearance of particular polypeptide bands and the accumulation of high-molecular-weight aggregates could be observed. Succinate was found to delay these effects. As a consequence of lipid peroxidation the succinate oxidase activity of mitochondria was decreased. The succinate dehydrogenase enzyme and the component(s) of the respiratory chain were inactivated. Succinate prevented the inactivation of succinate dehydrogenase but did not protect the other components of terminal oxidation chain. From the matrix enzymes the glutamate dehydrogenase retained its full activity but the NADP-linked isocitrate dehydrogenase was inactivated. The mitochondrial membranes became permeable to large protein molecules. Succinate prevented the inactivation of isocitrate dehydrogenase and delayed the release of protein molecules from mitochondria.
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PMID:Effect of succinate on mitochondrial lipid peroxidation. 2. The protective effect of succinate against functional and structural changes induced by lipid peroxidation. 303 29

The DNA sequence of the Bacillus subtilis sdh operon coding for the two succinate dehydrogenase subunits and cytochrome b-558 (the membrane anchor protein) has recently been established. We have now determined the extent of N-terminal processing of each polypeptide by radiosequence analysis. At the same time, direct evidence for the correctness of the predicted reading frames has been obtained. The cytochrome showed a ragged N-terminus, with forms lacking one residue, and is inserted across the membrane without an N-terminal leader-peptide. Covalently bound flavin was not detectable in B. subtilis succinate dehydrogenase expressed in Escherichia coli despite normal N-terminal processing of the apoprotein. This provides an explanation to why the succinate dehydrogenase synthesized in E. coli is not functional and demonstrates that host-specific factors regulate the coenzyme attachment.
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PMID:Processing of Bacillus subtilis succinate dehydrogenase and cytochrome b-558 polypeptides. Lack of covalently bound flavin in the Bacillus enzyme expressed in Escherichia coli. 310 91

Monospecific antibody to the respiratory NADH dehydrogenase from Paracoccus denitrificans was prepared by using as antigen specific immunoprecipitates containing NADH dehydrogenase which were excised from crossed-immunoelectrophoresis plates. The latter were run with selectively solubilized plasma membranes and antibodies against plasma membranes. The antibody immunoprecipitated NADH dehydrogenase from P. denitrificans membranes biosynthetically labelled with 14C and solubilized with a wide range of detergents. All immunoprecipitates contained the two subunits of Mr 48,000 and 25,000, in an approximate 1:1 stoichiometry, that had previously been assigned to NADH dehydrogenase. A polypeptide of Mr 46,000 in P. denitrificans membranes, previously shown to cross-react with a subunit-specific antibody to mitochondrial NADH dehydrogenase (complex I), was not detected in any immunoprecipitate. Under some conditions a third polypeptide, of Mr 31,000, was also detected, but in variable and non-stoichiometric amounts relative to the two other subunits. It was concluded that this polypeptide was incorporated into the immunoprecipitates as an artefact and that the polypeptides of Mr 48,000 and 25,000 are the sole polypeptides firmly identified in the NADH dehydrogenase. Flavoproteins were specifically radiolabelled by growth of P. denitrificans in the presence of [14C]riboflavin. Crossed immunoelectrophoresis of membranes from such cells showed that succinate dehydrogenase contained flavin, but that there was no detectable flavin in NADH dehydrogenase under these conditions. Analysis of excised immunoprecipitates of succinate dehydrogenase showed that flavin was covalently bound to a polypeptide of Mr 56,000. Flavin was retained by NADH dehydrogenase under mild conditions of detergent solubilization. Subsequent immunoprecipitation, followed by analysis of the acid-extracted flavin, established that FMN is a cofactor, in common with mitochondrial NADH-ubiquinone oxidoreductase (complex I).
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PMID:Immunochemical probing of the structure and cofactor of NADH dehydrogenase from Paracoccus denitrificans. 344 83


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