| 1. |
- Aevarsson, A, et al.
(författare)
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Ligands to the 2Fe iron-sulfur center in succinate dehydrogenase
- 1988
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Ingår i: FEBS Letters. - : Wiley. - 1873-3468 .- 0014-5793. ; 232:2, s. 298-302
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Tidskriftsartikel (refereegranskat)abstract
- 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 subtillis 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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| 2. |
- Carlsson, Peter, et al.
(författare)
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Bacillus subtilis citM, the structural gene for dihydrolipoamide transsuccinylase: cloning and expression in Escherichia coli
- 1987
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Ingår i: Gene. - : Elsevier BV. - 1879-0038 .- 0378-1119. ; 61:2, s. 217-224
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Tidskriftsartikel (refereegranskat)abstract
- The 2-oxoglutarate dehydrogenase multienzyme complex is composed of three different subenzymes: 2-oxoglutarate dehydrogenase (E1o), dihydrolipoamide transsuccinylase (E2o), and dihydrolipoamide dehydrogenase (E3). Bacillus subtilis E1o and E2o are encoded by the citK and citM genes, respectively. A 3.4-kb BamHI DNA fragment containing citK and citM markers was isolated from a library of B. subtilis DNA in Escherichia coli. Functional E2o was expressed from the cloned DNA both in B. subtilis and E. coli. E2o had an apparent Mr of 60000 when expressed in E. coli. The B. subtilis E2o component complemented an E. coli E2o-defective mutant in vivo and in vitro. It is concluded that functional B. subtilis E2o can be produced in E. coli and can interact with E. coli and E1o and E3 to form an active chimeric enzyme complex.
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| 3. |
- Carlsson, P., et al.
(författare)
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Genetic Characterization of Bacillus subtilis odhA and odhB, encoding 2-oxoglutarate dehydrogenase and dihydrolipoamide transsuccinylase, respectively
- 1989
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Ingår i: Journal of Bacteriology. - : American Society for Microbiology. - 0021-9193 .- 1098-5530. ; 171:7, s. 3667-3672
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Tidskriftsartikel (refereegranskat)abstract
- The 2-oxoglutarate dehydrogenase complex consists of three different subenzymes, the E1o (2-oxoglutarate dehydrogenase) component, the E2o (dihydrolipoyl transsuccinylase) component, and the E3 (dihydrolipoamide dehydrogenase) component. In Bacillus subtilis, the E1o and E2o subenzymes are encoded by odhA and odhB, respectively. A plasmid with a 6.8-kilobase-pair DNA fragment containing odhA and odhB was isolated. Functional E1o and E2o are expressed from this plasmid in Escherichia coli. Antisera generated against B. subtilis E1o and E2o expressed in E. coli reacted with antigens of the same size from B. subtilis. The nucleotide sequence of odhB and the terminal part of odhA was determined. The deduced primary sequence of B. subtilis E2o shows striking similarity to the corresponding E. coli protein, which made it possible to identify the lipoyl-binding lysine residue as well as catalytic histidine and aspartic acid residues. An mRNA of 4.5 kilobases hybridizing to both odhA and odhB probes was detected, indicating that odhA and odhB form an operon.
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| 4. |
- Carlsson, Peter, et al.
(författare)
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In vitro complementation of Bacillus subtilis and Escherichia coli 2-oxoglutarate dehydrogenase complex mutants and genetic mapping of B. subtilis citK and citM mutations
- 1986
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Ingår i: FEMS Microbiology Letters. - : Oxford University Press (OUP). - 1574-6968 .- 0378-1097. ; 37:3, s. 373-378
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Tidskriftsartikel (refereegranskat)abstract
- AbstractThe 2-oxoglutarate dehydrogenase complex of the tricarboxylic acid cycle (TCA) consists of multiple copies of 3 different subenzymes; E1, E2 and E3. The E3 subenzyme is also a component of the pyruvate dehydrogenase complex. Bacillus subtilis 2-oxoglutarate dehydrogenase mutants were studied. The mutants defective in E1, E2 and E3 subenzyme activity, respectively, could be separated into 3 groups by biochemical complementation analyses. The groups correspond to the citK, citM and citL genes. A B. subtilis subenzyme defect, probably E1, could be complemented with the corresponding Escherichia coli wild-type subenzyme and vice versa. Mutations in citK and citM are closely linked. The gene order kauA--- ---citK-citM was determined from 3-factor transformation crosses. It is concluded that the gene organization and the subenzyme structure of the 2-oxoglutarate dehydrogenase complex are similar in B. subtilis and E. coli.
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| 5. |
- Fridén, H, et al.
(författare)
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Cytochrome b558 of Bacillus subtilis
- 1988
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Ingår i: Cytochrome Systems : Molecular Biology and Bioenergetics - Molecular Biology and Bioenergetics. - 9781461290780 - 9781461319412 ; , s. 641-647
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Bokkapitel (refereegranskat)abstract
- The membranebound tricarboxylic acid cycle enzyme succinate dehydrogenase (SDH) is associated with a b-type cytochrome in many organisms. 1,2 The cytochrome b is often found in stoichiometric amounts in isolated succinate-ubiquinone oxidoreductase (complex II) from bovine heart,3Neurospora crassa,4Ascaris suum5 and plant6 mitochondria as well as in SDH complexes isolated from both Gram-negative and Gram-positive8,9 bacteria whereas yeast (Saccharomyces cerevisiae) apparently lacks this type of cytochrome.10
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| 6. |
- Fridén, H, et al.
(författare)
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Genetic and biochemical characterization of Bacillus subtilis mutants defective in expression and function of cytochrome b-558
- 1987
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Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 168, s. 695-701
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Tidskriftsartikel (refereegranskat)abstract
- Bacillus subtilis succinate dehydrogenase is bound to the cytoplasmic membrane by cytochrome b-558, a 23-kDa transmembrane protein which also functions as electron acceptor to the dehydrogenase. The structural gene for the apocytochrome, sdhC, has previously been cloned and sequenced. In this work the structure and translation of cytochrome b-558 was studied in different sdhC mutants. Mutant cytochrome was analyzed both in B. subtilis and after amplification in Escherichia coli. It is concluded that amino acid substitutions in the C-terminal half of the cytochrome can prevent the binding of succinate dehydrogenase without affecting membrane binding of the cytochrome protein or heme ligation. Mutagenesis of His-113 excludes this residue as an axial heme ligand. A base-pair exchange of G to A in the ribosome-binding sequence of sdhC was found to reduce cytochrome b-558 translation about tenfold in B. subtilis, whereas the mutation had no effect on translation in E. coli. Translation of the two succinate dehydrogenase genes from the sdhCAB polycistronic transcript does not seem to be coupled to translation of sdhC. Less than 10% of the wild-type amount of membrane-bound succinate dehydrogenase in B. subtilis still allows growth on non-fermentable substrate, but makes the dehydrogenase a limiting enzyme in the tricarboxylic acid cycle and leads to succinate accumulation.
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| 7. |
- Hederstedt, Lars, et al.
(författare)
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Covalent binding of FAD to Bacillus subtilis succinate dehydrogenase
- 1987
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Ingår i: Flavins and Flavoproteins : Proceedings of the Ninth International Symposium, Atlanta, Georgia, U. S. A. June 7-12, 1987 - Proceedings of the Ninth International Symposium, Atlanta, Georgia, U. S. A. June 7-12, 1987. - 3110109506 - 0899253067 ; , s. 729-736
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Konferensbidrag (refereegranskat)
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| 8. |
- Hederstedt, Lars, et al.
(författare)
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New properties of Bacillus subtilis succinate dehydrogenase altered at the active site
- 1989
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Ingår i: Biochemical Journal. - : Portland Press Ltd.. - 0264-6021 .- 1470-8728. ; 260:2, s. 491-497
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Tidskriftsartikel (refereegranskat)abstract
- Mammalian and Escherichia coli succinate dehydrogenase (SDH) and E. coli fumarate reductase apparentlycontain an essential cysteine residue at the active site, as shown by substrate-protectable inactivation withthiol-specific reagents. Bacillus subtilis SDH was found to be resistant to this type of reagent and containsan alanine residue at the amino acid position equivalent to the only invariant cysteine in the flavoproteinsubunit of E. coli succinate oxidoreductases. Substitution of this alanine, at position 252 in the flavoprotein subunit of B. subtilis SDH, by cysteine resulted in an enzyme sensitive to thiol-specific reagents and protectable by substrate. Other biochemical properties of the redesigned SDH were similar to those of the wild-type enzyme. It is concluded that the invariant cysteine in the flavoprotein of E. coli succinate oxidoreductases corresponds to the active site thiol. However, this cysteine is most likely not essential for succinate oxidation and seemingly lacks an assignable specific function. An invariant arginine in juxtaposition to Ala-252 in the flavoprotein of B. subtilis SDH, and to the invariant cysteine in the E. coli homologous enzymes, is probably essential for substrate binding.
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| 9. |
- Lofstedt, Christer, et al.
(författare)
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Pheromone dialects in European turnip moths Agrotis segetum
- 1986
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Ingår i: Oikos. - : JSTOR. - 0030-1299. ; 46:2, s. 250-257
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Tidskriftsartikel (refereegranskat)abstract
- Female pheromone gland extracts from cultures of Agrotis segetum originating from Sweden, France, Hungary and England were analysed for pheromone components and precursors (fatty acids). The pheromone blends were similar in moths from the Swedish, English and Hungarian populations, whereas the French diverged with a much higher amount of (Z)-7-decenyl acetate relative to the homologous pheromone components (Z)-7-dodecenyl acetate and (Z)-9-tetradecenyl acetate. -from Authors
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| 10. |
- Lundberg, Peter, et al.
(författare)
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Permeabilization of Plant Cells: 31P NMR Studies of the Permeability of the Tonoplast
- 1986
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Ingår i: Plant Cell Reports. - : Springer. - 0721-7714 .- 1432-203X. ; 5, s. 13-16
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Tidskriftsartikel (refereegranskat)abstract
- A suspension culture of Catharanthus roseus has been used to study the permeability of cell membranes after treatment with various concentrations of a permeabilizing agent (DMSO). The uptake and release (after permeabilization) of inorganic phosphate (Pi) by cells have been investigated by 32P radiotracer and non-invasive phosphorus-31 NMR experiments. These studies have demonstrated that measurements of the Pi-efflux from plant cells provide a reliable measure of the permeability of the tonoplast.
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