W Eisenreich

..Bioinformatical steady-state network analyses and flux distribution predictions confirmed the experimental data and predicted metabolite fluxes through the enzymes of the pathways under study...

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..This demonstrates the potential of photo-CIDNP in unraveling reactive intermediates in protein function...

..However, there is very little molecular data available for either the rubber polymer itself or its biosynthesis in T. koksaghyz...

..Riboflavin synthase is therefore a potential target for the development of antiinfective drugs...

..For this purpose, Spodoptera frugiperda cells were grown in a complex medium containing [U-13C6]glucose. In a second experiment, cultures of S. frugiperda were grown in the presence of 15N-phenylalanine...

..This review summarizes some of the recent advances of high-resolution NMR spectroscopy in the field of plant sciences...

..Information on this pathway could provide the basis for the development of new antibiotics, herbicides and antimalarials...

..The perturbation method described can be adapted to a wide variety of experimental systems and isotope-labeled precursors...

..The data showed that the isoprenoid precursors of zeaxanthin were biosynthesized via the mevalonate pathway. The microorganism was found to utilize glucose mainly via the Entner-Doudoroff pathway...

..The experimental data can be integrated into a detailed biosynthetic scheme involving a 1,5-hydride shift. The postulated involvement of the 1,5-hydride shift was confirmed by an incorporation experiment with [6,6-(2)H(2)]glucose...

..This strongly indicates that the former enzymes are in the FO conformation and the other two are in the FR conformation. The data are discussed briefly in the context of published NMR data obtained with a variety of flavoproteins...

..Detailed knowledge about the mechanisms of this novel route may benefit the development of novel antibiotics, antimalarials and herbicides...

..13)C Chemical shifts of FMN are shown to be differently modulated by complexation with the LOV domains under study, indicating slight differences in the binding interactions of FMN and the apoproteins...

..This compound does not serve as substrate for the formation of carotenoids by isolated chromoplasts and is assumed to be an in vitro product without metabolic relevance...

..The overall yield based on the respective isotope-labeled starting material is approximately 50%...

..The enzyme is a potential target for antimalarial drugs directed at the nonmevalonate pathway of isoprenoid biosynthesis...

..The sequence of E. coli YchB protein is similar to that of the protein predicted by the tomato cDNA pTOM41 (30% identity), which had been implicated in the conversion of chloroplasts to chromoplasts...

..Enzyme-catalyzed fragmentation of this compound under formation of riboflavin can occur easily by a sequence of two elimination reactions...

..The Michaelis constants for 4-diphosphocytidyl-2C-methyl-d-erythritol and CTP were 500 microM and 114 microM, respectively...

..The data support the conclusion that the formylamino pyrimidine derivative is an intermediate in the overall reaction catalyzed by GTP cyclohydrolase I...

..On the other hand, the reaction catalyzed by sepiapterin reductase does not involve any detectable incorporation of solvent protons into tetrahydrobiopterin...

..Hypothetical mechanisms involving conserved cysteine residues are proposed for the enzymatic conversion of 2C-methyl-D-erythritol 2,4-cyclodiphosphate into 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate catalyzed by the GcpE protein...

..Divalent metal ions, preferably Mg(2+), are required for activity. Neither the tomato enzyme nor the E. coli ortholog catalyzes the phosphorylation of isopentenyl monophosphate...

..Stereospecific transfer of H(Si) from C-4 of the cofactor identifies the Dxr protein of E. coli as a class B dehydrogenase...

..The genes specifying these enzymes have been cloned from bacteria, plants and protozoa. Their expression in recombinant bacterial hosts has opened the way to the identification of several novel pathway intermediates...

..A gene from Arabidopsis thaliana with similarity to ygbP carries a putative plastid import sequence, which is well in line with the assumed localization of the deoxyxylulose pathway in the plastid compartment of plants...

..Carbon atom C1' of compound Z is derived from carbon atom C8 of a guanine derivative. The remodeling of the carbon skeleton of the pentose and purine moieties proceed via intramolecular rearrangement reactions...

..Using photometric and NMR spectroscopic assays, we screened extracts of Mediterranean plants for inhibitors of the enzyme. Strongest inhibitory activity was found in leaf extracts of Cercis siliquastrum...

..The enzyme reaction is cooperative with a Hill coefficient of 1.3. Inhibition by pyrophosphate is competitive. Inhibition by orthophosphate is partially uncompetitive at low concentration and competitive at concentrations above 6 mm...

..The results provide the basis for the development of novel anti-infective drugs...

..6,7-Dimethyl-8-ribityllumazine synthase and the archaeal riboflavin synthase appear to have diverged early in the evolution of Archaea from a common ancestor...

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..Exogenous acetate served as an efficient precursor of sitosterol, as well as of amino acids of the aspartate and glutamate family; in comparison, metabolites formed in the plastidic compartments showed low acetate incorporation...

..GC-olfactometry revealed a sweet coconut-like odor for the cis-thio- and pleasant mushroom-like flavors for the cis-thiono- and trans-dithio-derivatives of whiskey lactone...

..Bx2 through Bx5 encode cytochrome P450-dependent monooxygenases that catalyze four consecutive hydroxylations and one ring expansion to form the highly oxidized DIBOA...

..The pH optimum is 8.0. NADH can substitute for NADPH, albeit at a low rate (14% as compared to NADPH). The enzyme catalyzes the reverse reaction at a rate of 2.1 micromol x min(-1) x mg(-1)...

..The further metabolism is thought to lead to 3-oxoadipyl-CoA, the intermediate at which the conventional and the unorthodox pathways merge...

..aeolicus IspE directs the OH group of a tyrosine residue into a pocket in the active site. In the E. coli enzyme, on the other hand, this pocket is lined by phenylalanine and has a more pronounced hydrophobic character...

..Chemical shift modulation of the side chain and chromophore carbon atoms due to protein/ligand interaction is discussed on the basis of the sequence similarity between lumazine protein and riboflavin synthase...

..The pentacyclic intermediates of trimeric and pentameric riboflavin synthases are diastereomers...

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..The preparation of 4-diphosphosphocytidyl-2C-methyl-D-erythritol 2-phosphate in multigram quantities is described for the first time...

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..These data show that the N-terminal domain is the unique site for ligand binding in lumazine protein...

..Riboflavin is bound to a shallow cavity in the N-terminal domain of lumazine protein, whereas the C-terminal domain lacks a ligand...

..This experimental concept appears ripe for application to a wide variety of problems in plant physiology...

..This comprehensive analysis of the central carbon metabolism of I. hospitalis revealed further evidence for the unexpected and unexplored diversity of metabolic pathways within the (hyperthermophilic) archaea...

..The assays can be monitored photometrically and have been shown to be robust, as indicated by Z factors 0.87. A (13)C NMR assay for hit verification of 3,4-dihydroxy-2-butanone 4-phosphate synthase inhibitors is also reported...

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..This structure provides useful insights for future structure-based developments of inhibitors for the parasite enzymes...

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..These results are in agreement with the known three-dimensional structure of the M. jannaschii enzyme...

..The results unambiguously demonstrate a dioxygenase mechanism for the carotenase AtCCD1 from A. thaliana...

..All available data indicate that the respective pentacyclic intermediates of the M. jannaschii and E. coli enzymes are diastereomers...

..The starter unit, 3-hydroxybenzoyl-CoA, is obtained from an early shikimate pathway intermediate. Phenylalanine, cinnamic acid and benzoic acid were ruled out as intermediates...

..Regions harboring strictly conserved residues that are implicated in substrate binding or catalysis remain largely disordered even in the presence of FMN...

..The impact of structural modification of the boxA motif on the affinity for NusB protein as observed by 1H15N heterocorrelation was analysed by a generic algorithm...

..Both sites are connected by a spacer of three methylene groups. The substrate molecule, 1-d-deoxyxylulose 5-phosphate, can be superimposed onto fosmidomycin, explaining the stereochemical course of the reaction...

..The striking similarities of IspG and IspH protein are discussed, and plausible mechanistic schemes are proposed for the two reactions...

..The overall yields of riboflavin based on isotope-labeled glucose are 35-50%...

..The model suggests that the substrate molecule at the C-terminal domain donates a four-carbon unit to the substrate molecule bound at the N-terminal domain of an adjacent subunit in the oligomer...

..A cluster of charged amino acid residues comprising arginine 25, glutamates 26 and 28, and aspartates 21 and 30 is essential for catalytic activity. Histidine 164 and glutamate 185 were also shown to be essential for catalytic activity...

..The low intrinsic catalytic activities of wild-type E. coli cell extract and isolated chromoplasts of red pepper (Capsicum annuum) are enhanced by the addition of purified recombinant IspH protein...

..The compound was shown to be identical with the product of IspG protein, which serves as an intermediate in the nonmevalonate terpene biosynthetic pathway...

..The product was analyzed by multinuclear NMR spectroscopy. The data show that the carbinol group of enzymatically formed 6-hydroxymethyl-dihydropterin contained 2H predominantly in the pro-S position...

..The leucine moiety of [(13)C-formyl,(15)N]-N-formylleucine (10) was diverted to lipstatin under loss of the (13)C-labeled formyl residue...

..The protein forms homotrimers that tightly bind one zinc ion per subunit at the active site, which helps to position the substrate for direct attack of the 2-phosphate group on the beta-phosphate...

..The subsequent beta-oxidation-type degradation of the resulting CoA dicarboxylate via beta-ketoadipyl-CoA to succinyl-CoA and acetyl-CoA appears to be catalyzed by the PaaJ, PaaF and PaaH proteins...

..Our model therefore provides an accurate template to facilitate the structure-based design of broad-spectrum antimicrobial agents...

..The (Fe,Ni)S-dependent urea hydrolysis could have been the evolutionary precursor of the nickelenzyme urease. The results support the theory of a chemoautotrophic origin of life with a CO-driven, (Fe,Ni)S-dependent primordial metabolism...

..The complex reaction is part of a widely distributed new principle of aerobic aromatic metabolism in which all intermediates are coenzyme A thioesters and the actual ring-cleavage reaction does not require molecular oxygen...

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..The observation that MECP synthase binds three metabolites that are produced by enzymes two, three and four stages downstream in isoprenoid biosynthesis suggests that feedback regulation of the non-mevalonate pathway is possible...

..Replacement of any of the conserved cysteine residues reduced the catalytic activity by a factor of more than 70 000...

..We propose that complex formation of the three enzymes at the core of the DOXP pathway can produce an assembly localizing 18 catalytic centers for the early stages of isoprenoid biosynthesis...

..The benzoyl-CoA oxygenase system has very low similarity to known (di)oxygenase systems and is the first member of a new enzyme family...

..Some Archaea have eubacterial type riboflavin synthases which may have been acquired by lateral gene transfer...

..A hitherto unknown family of IPP isomerases using FMN as coenzyme has been discovered recently in Archaea and certain eubacteria...

..The isotope-labeled samples enabled a comprehensive NMR analysis of 6,7-dimethyl-8-ribityllumazine. Isotopolog libraries of a wide variety of microbial metabolites can be produced by the same experimental approach...

..These bifunctional proteins are potential drug targets in several human pathogens (e.g. Helicobacter pylori, C. jejuni and Treponema pallidum)...

..These data show that the riboflavin biosynthesis in plants proceeds by the same reaction steps as in eubacteria, whereas fungi use a different pathway...

..Type II isomerase is essential in some important human pathogens including Staphylococcus aureus and Enterococcus faecalis where it may represent a novel target for anti-infective therapy...

..Various yeasts produced 3-mercaptohexanol starting from 1 as well as from 5. The reactions proceeded without preferential formation of one of the enantiomers...

..coli strain engineered for the expression of the ispH (lytB) gene in addition to recombinant xylB and ispCDEFG genes...