Brucella melitensis is the etiological agent responsible for brucellosis. Present in the B. melitensis genome is a 116-residue protein related to arsenate reductases (Bm-YffB; BR0369). Arsenate reductases (ArsC) convert arsenate ion (H(2)AsO(4)(-)), a compound that is toxic to bacteria, to arsenite ion (AsO(2)(-)), a product that may be efficiently exported out of the cell. Consequently, Bm-Yff...

Cytochrome b was identified as one of the ubiquinone-binding proteins in bovine heart mitochondrial ubiquinol-cytochrome c reductase by photoaffinity labeling using 3-azido-2-methyl-5-methoxy-6-(3,7-dimethyl[3H]-octyl)-1,4-benzoquinone ([3H]azido-Q). The [3H]azido-Q-labeled cytochrome b protein was purified to homogeneity from the azido-Q-labeled ubiquinol-cytochrome c reductase by a procedure ...

The creation of a synthetic microbe that can harvest energy from sunlight to drive its metabolic processes is an attractive approach to the economically viable biosynthetic production of target compounds. Our aim is to design and engineer a genetically tractable non-photosynthetic microbe to produce light-harvesting molecules. Previously we created a modular, multienzyme system for the heterolo...

From a single amethopterin-resistant organism, Streptococcus faecium var. durans strain A, two different dihydrofolate reductases have been obtained as essentially homogeneous proteins in good yield. One of the reductases has a similar substrate specificity and turnover number (about 8000 moles per min per mole of enzyme) to the single reductase found in the amethopterin-sensitive strain of S. ...

NADH-cytochrome b5 reductases of rat liver microsomes, mitochondria, and heavy and light Golgi fractions (GF3 and GF 1+2) were compared by antibody inhibition and competition experiments, by peptide mapping, and by CNBr fragment analysis. The water-soluble portion of the microsomal enzyme, released by lysosomal digestion and purified by a published procedure, was used to raise antibodies in rab...

The genes encoding flavin mononucleotide-containing oxidoreductases, designated xenobiotic reductases, from Pseudomonas putida II-B and P. fluorescens I-C that removed nitrite from nitroglycerin (NG) by cleavage of the nitroester bond were cloned, sequenced, and characterized. The P. putida gene, xenA, encodes a 39,702-Da monomeric, NAD(P)H-dependent flavoprotein that removes either the termina...

Ribonucleotide reductases catalyze in all living organisms the production of the deoxyribonucleotides required for DNA replication and repair. Their appearance during evolution was a prerequisite for the transition from the "RNA world," where RNA sufficed for both catalysis and information transfer, to today's situation where life depends on the interplay among DNA, RNA, and protein. Three clas...

Ribonucleotide reductases provide the building blocks for DNA synthesis. Three classes of enzymes are known, differing widely in amino acid sequence but with similar structural motives and allosteric regulation. Class I occurs in eukaryotes and aerobic prokaryotes, class II occurs in aerobic and anaerobic prokaryotes, and class III occurs in anaerobic prokaryotes. The eukaryote Euglena gracilis...

Brassinosteroids are important phytohormones for plant growth and development. In soybean (Glycine max), BR receptors have been identified, but the genes encoding BR biosynthesis-related enzymes remain poorly understood. Here, we found that the soybean genome encodes eight steroid reductases (GmDET2a to GmDET2h). Phylogenetic analysis grouped 105 steroid reductases from moss, fern and higher pl...