Sökresultat

Filtyp

Din sökning på "*" gav 541684 sökträffar

The structural gene for aspartokinase II in Bacillus subtilis is closely linked to the sdh operon

The aecA and aecB loci map at 250 and 290 degrees, respectively, on the Bacillus subtilis chromosomal genetic map. The aecB locus has been proposed as the structural gene for aspartokinase II. From DNA sequence analyses and comparisons to the sequence of the aspartokinase II gene, it can be concluded that the structural gene for aspartokinase II is located close to sdh at 250 degrees and cannot be

Genetic Characterization of Bacillus subtilis odhA and odhB, encoding 2-oxoglutarate dehydrogenase and dihydrolipoamide transsuccinylase, respectively

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 o

New properties of Bacillus subtilis succinate dehydrogenase altered at the active site

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 c

Expression and flavinylation of Arthrobacter oxydans 6-hydroxy-D-nicotine oxidase in Bacillus subtilis

6-Hydroxy-d-nicotine oxidase (6-HDNO) of Arthrobacter oxydans, an enzyme inducible by dl-nicotine, contains FAD covalently bound via an 8α-N(3)His linkage. Expression of the gene encoding 6-HDNO and flavinylation of the protein were studied in Bacillus subtilis. In this heterologous system the following findings were made. 1. An enzymically active covalently flavinylated 6-HDNO of normal size can

Cytochrome b558 of Bacillus subtilis

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 an

Ligands to the 2Fe iron-sulfur center in succinate dehydrogenase

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 cyste

Bacillus subtilis citM, the structural gene for dihydrolipoamide transsuccinylase: cloning and expression in Escherichia coli

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. subtili

Genetic and biochemical characterization of Bacillus subtilis mutants defective in expression and function of cytochrome b-558

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 cytoc

Processing of Bacillus subtilis succinate dehydrogenase and cytochrome b-558 polypeptides

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. Th

Deletion of the Bacillus subtilis sdh operon

Plasmid pKIM2 carries the Bacillus subtilis sdh operon and adjacent regions of the bacterial chromosome. The plasmid replicates in Escherichia coli but not in B. subtilis. Different portions of the sdh operon were removed from pKIM2 and replaced by a cat gene derived from pC194. A series of plasmids carrying sdh deletions was thus derived. Plasmid DNA was linearized at restriction sites within the

Nucleotide sequence encoding the flavoprotein and the iron-sulfur protein subunits of the Bacillus subtilis PY79 succinate dehydrogenase complex

The nucleotide sequence of a 2.7-kilobase segment of DNA containing the sdhA and sdhB genes encoding the flavoprotein (Fp, sdhA) and iron-sulfur protein (Ip, sdhB) subunits of the succinate dehydrogenase of Bacillus subtilis was determined. This sequence extends the previously reported sequence encoding the cytochrome b558 subunit (sdhC) and completes the sequence of the sdh operon, sdhCAB. The pr

In vitro complementation of Bacillus subtilis and Escherichia coli 2-oxoglutarate dehydrogenase complex mutants and genetic mapping of B. subtilis citK and citM mutations

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

Molecular properties, genetics, and biosynthesis of Bacillus subtilis succinate dehydrogenase complex

This chapter discusses the molecular properties, genetics, and biosynthesis of Bacillus subtilis succinate dehydrogenase complex. The citric acid cycle enzyme succinate dehydrogenase (SDH) is a membrane-bound iron-sulfur flavoprotein. Mitochondrial and bacterial SDH and membrane-bound fumarate reductase in anaerobic and facultative bacteria are similar in composition. SDH and also fumarate reducta

Rare Variant Analysis of Human and Rodent Obesity Genes in Individuals with Severe Childhood Obesity

Obesity is a genetically heterogeneous disorder. Using targeted and whole-exome sequencing, we studied 32 human and 87 rodent obesity genes in 2,548 severely obese children and 1,117 controls. We identified 52 variants contributing to obesity in 2% of cases including multiple novel variants in GNAS, which were sometimes found with accelerated growth rather than short stature as described previousl

Electron-paramagnetic-resonance spectroscopy of Bacillus subtilis cytochrome b558 in Escherichia coli membranes and in succinate dehydrogenase complex from Bacillus subtilis membranes

Cytochrome b558 of the Bacillus subtilis succinate dehydrogenase complex was studied by electron-paramagnetic-resonance (EPR) spectroscopy. The cytochrome amplified in Escherichia coli membranes by expression of the cloned cytochrome gene and in the succinate dehydrogenase complex immunoprecipitated from solubilized B. subtilis membranes, respectively, is shown to be low spin with a highly anisotr

Modification of bovine heart succinate dehydrogenase with ethoxyformic anhydride and Rose bengal: Evidence for essential histidyl residues protectable by substrates

Purified and membrane-bound succinate dehydrogenase (SDH) from bovine heart mitochondria was inhibited by the histidine-modifying reagents ethoxyformic anhydride (EFA) and Rose Bengal in the presence of light. Succinate and competitive inhibitors protected against inhibition, and decreased the number of histidyl residues modified by EFA. The essential residue modified by EFA was not the essential

Bacillus subtilis mutant succinate dehydrogenase lacking covalently bound flavin: Identification of the primary defect and studies on the iron-sulfur clusters in mutated and wild- type enzyme

Succinate dehydrogenase consists of two protein subunits and contains one FAD and three iron-sulfur clusters. The flavin is covalently bound to a histidine in the larger, Fp, subunit. The reduction oxidation midpoint potentials of the clusters designated S-l, S-2, and S-3 in Bacillus subtilis wild-type membrane-bound enzyme were determined as +80, -240, and -25 mV, respectively. Magnetic spin inte

Effect of burner geometry on swirl stabilized methane/air flames : A joint LES/OH-PLIF/PIV study

Large eddy simulation (LES) using a transported PDF model and OH-PLIF/PIV experiments were carried out to investigate the quarl effects on the structures of swirl stabilized methane/air flames. Two different quarls were investigated, one straight cylindrical quarl and one diverging conical quarl. The experiments show that the flames are significantly different with the two quarls. With the straigh

Charging Information Services for BEVs – Two Competing and Complementary Business Models

This paper examines information services in association with charging services, and in particular players that offer information services related to charging service offerings from many different operators. It identifies two main types of business models through studying and comparing 25 European charging information service providers. For one type of players the paper analyses the network charact