Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D02011 (FAD)
 5,530 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major pigment produced by Staphylococcus aureus Newman is the deep-yellow carotenoid 4,4'-diaponeurosporene; after prolonged cultivation, this pigment is in part converted to the orange end product staphyloxanthin. From this strain a 3.5-kb DNA fragment was identified which after being cloned into Escherichia coli and Staphylococcus carnosus conferred the ability to produce 4,4'-diaponeurosporene. DNA sequencing of this fragment revealed two open reading frames (ORFs) which are very likely cotranscribed. ORF1 encodes a 254-amino-acid hydrophobic protein, CrtM (M(r), 30,121). The deduced sequence of CrtM exhibits in three domains similarities to the sequences of Saccharomyces cerevisiae and human squalene synthases and phytoene synthases of various bacteria. ORF2 encodes a 448-amino-acid hydrophobic protein, CrtN, with an M(r) of 50,853 whose deduced sequence is similar to those of phytoene desaturases of other bacteria. At the N terminus of CrtN a classical FAD-, NAD(P)-binding domain is found. Spectrophotometry and gas chromatography-mass spectrometry analyses of the carotenoid production of E. coli and S. carnosus clones containing either ORF1 or both ORFs together suggest that ORF1 and ORF2 represent the dehydrosqualene synthase gene (crtM) and the dehydrosqualene desaturase gene (crtN), respectively. The results furthermore suggest that the biosynthesis of 4,4'-diaponeurosporene starts with the condensation of two molecules of farnesyl diphosphate by dehydrosqualene synthase (CrtM); it is shown that the reaction product of this enzyme is dehydrosqualene and not squalene. Dehydrosqualene (4,4'-diapophytoene) is successively dehydrogenated by a desaturase (CrtN) to form the yellow main intermediate 4,4'-diaponeurosporene.
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PMID:Genetic and biochemical analyses of the biosynthesis of the yellow carotenoid 4,4'-diaponeurosporene of Staphylococcus aureus. 800 98

Epoxypropane isomerase from Xanthobacter Py2 has been resolved into at least two components (A and B) by ion-exchange chromatography. Both components were required for the degradation of epoxypropane and were purified further. Component A was apparently homohexameric with a subunit M(r) of about 44,000, and possessed NAD(+)-dependent dihydrolipoamide dehydrogenase activity and lipoamide reductase activity. It was sensitive to inhibition by o-phenanthroline and the thiol-specific reagents N-ethylmaleimide(NEM)and p-chloromercuribenzoate. Component B was homodimeric with a subunit M(r), of 62,170 and contained 2 mol.mol-1 FAD. It had an NADPH-dependent lipoamide reductase activity which was sensitive to NEM and p-chloromercuribenzoate. The N-terminal amino acid sequences and monomer sizes of components A and B correspond to those of ORF1 and ORF3 respectively (ORF = open reading frame) of a recently published sequence of a clone which complements mutants unable to degrade epoxypropane. NADPH was found to replace the need for a low-M(r), fraction in epoxypropane degradation assays containing components A and B and NAD+. The predicted amino acid sequence of component A (ORF1) has been analysed and shown to contain a potential ADP binding site near the N-terminus and putative cofactor binding domain near the C-terminus, with sequence similarity to the biotinyl and lipoyl binding domains of biotin-dependent carboxylases and 2-oxoacid dehydrogenases respectively. A reaction mechanism for epoxypropane degradation, incorporating recent evidence for combined isomerization and carboxylation to acetoacetate, is discussed.
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PMID:Purification and characterization of two components of epoxypropane isomerase/carboxylase from Xanthobacter Py2. 891 87