- Methyl-Shifted Farnesyldiphosphate Derivatives Are Substrates for Sesquiterpene Cyclases
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New sesquiterpene backbones are accessible after biotransformation of presilphiperfolan-8β-ol synthase (BcBOT2), a fungal sesquiterpene synthase, with non-natural farnesyldiphosphates in which methyl groups are shifted by one position toward the diphosphate terminus. One of the macrocycles formed, a new germacrene A derivative, undergoes a Cope rearrangement to iso-β-elemene. Three of the new terpenoids show olfactoric properties that range from an intense peppery note to a citrus, ozone-like, and fruity scent.
- Harms, Vanessa,Schr?der, Benjamin,Oberhauser, Clara,Tran, Cong Duc,Winkler, Sven,Dr?ger, Gerald,Kirschning, Andreas
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supporting information
p. 4360 - 4365
(2020/06/08)
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- Exploiting the Synthetic Potential of Sesquiterpene Cyclases for Generating Unnatural Terpenoids
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The substrate flexibility of eight purified sesquiterpene cyclases was evaluated using six new heteroatom-modified farnesyl pyrophosphates, and the formation of six new heteroatom-modified macrocyclic and tricyclic sesquiterpenoids is described. GC-O analysis revealed that tricyclic tetrahydrofuran exhibits an ethereal, peppery, and camphor-like olfactoric scent.
- Oberhauser, Clara,Harms, Vanessa,Seidel, Katja,Schr?der, Benjamin,Ekramzadeh, Kimia,Beutel, Sascha,Winkler, Sven,Lauterbach, Lukas,Dickschat, Jeroen S.,Kirschning, Andreas
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supporting information
p. 11802 - 11806
(2018/09/10)
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- Characterization of the first naturally thermostable terpene synthases and development of strategies to improve thermostability in this family of enzymes
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The terpenoid family of natural products is being targeted for heterologous microbial production as a cheaper and more reliable alternative to extraction from plants. The key enzyme responsible for diversification of terpene structure is the class-I terpene synthase (TS), and these often require engineering to improve properties such as thermostability, robustness and catalytic activity before they are suitable for industrial use. Improving thermostability typically relies on screening a large number of mutants, as there are no naturally thermostable TSs described upon which to base rational design decisions. We have characterized the first examples of natural TSs exhibiting thermostability, which catalyse the formation of the sesquiterpene τ-muurolol at temperatures up to 78 °C. We also report an enzyme with a kcat value of 0.95 s?1 at 65 °C, the highest kcat recorded for a bacterial sesquiterpene synthase. In turn, these thermostable enzymes were used as a model to inform the rational engineering of another TS, with the same specificity but low sequence identity to the model. The newly engineered variant displayed increased thermostability and turnover. Given the high structural homology of the class-I TS domain, this approach could be generally applicable to improving the properties of other enzymes in this class. Database: Model data are available in the PMDB database under the accession number PM0080780.
- Styles, Matthew Q.,Nesbitt, Edward A.,Marr, Scott,Hutchby, Marc,Leak, David J.
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p. 1700 - 1711
(2017/06/08)
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- Enantioselective inhibition of squalene synthase by aziridine analogues of presqualene diphosphate
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(Figure Presented) Squalene synthase catalyzes the conversion of two molecules of (E,E)-farnesyl diphosphate to squalene via the cyclopropylcarbinyl intermediate, presqualene diphosphate (PSPP). Since this novel reaction constitutes the first committed step in sterol biosynthesis, there has been considerable interest and research on the stereochemistry and mechanism of the process and in the design of selective inhibitors of the enzyme. This paper reports the synthesis and characterization of five racemic and two enantiopure aziridine analogues of PSPP and the evaluation of their potencies as inhibitors of recombinant yeast squalene synthase. The key aziridine-2-methanol intermediates (6-OH, 7-OH, and 8-OH) were obtained by N-alkylations or by an N-acylation-reduction sequence of (±)-, (2R,3S)-, and (2S,3R)-2,3-aziridinofarnesol (9-OH) protected as tert-butyldimethylsilyl ethers. SN2 displacements of the corresponding methanesulfonates with pyrophosphate and methanediphosphonate anions afforded aziridine 2-methyl diphosphates and methanediphosphonates bearing N-undecyl, N-bishomogeranyl, and N-(α-methylene)bishomogeranyl substituents as mimics for the 2,6,10-trimethylundeca-2,5,9-trienyl side chain of PSPP. The 2R,3S diphosphate enantiomer bearing the N-bishomogeranyl substituent corresponding in absolute stereochemistry to PSPP proved to be the most potent inhibitor (IC50 1.17 ± 0.08 M in the presence of inorganic pyrophosphate), a value 4-fold less than that of its 2S,3R stereoisomer. The other aziridine analogues bearing the N-(α-methylene)bishomogeranyl and N-undecyl substituents, and the related methanediphosphonates, exhibited lower affinities for recombinant squalene synthase.
- Koohang, Ali,Bailey, Jessica L.,Coates, Robert M.,Erickson, Hans K.,Owen, David,Poulter, C. Dale
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supporting information; experimental part
p. 4769 - 4777
(2010/09/10)
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- IspG converts an epoxide substrate analogue to (E)-4-hydroxy-3-methylbut-2- enyl diphosphate: Implications for IspG catalysis in isoprenoid biosynthesis
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(Chemical Equation Presented) IspG is an intriguing enzyme in bacteria, parasite, and plant isoprenoid biosynthesis, and its catalytic mechanism remains elusive. We report here the synthesis of (2R,3R)-4-hydroxy-3-methyl-2,3- epoxybutanyl diphosphate (Epoxy-HMBPP), a proposed intermediate in one of the frequently cited mechanistic models. We have also demonstrated that this epoxide analogue is a catalytically competent IspG substrate. This study represents the first mechanistic study of this important enzyme.
- Nyland II, Rodney L.,Xiao, Youli,Liu, Pinghua,Freel Meyers, Caren L.
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supporting information; experimental part
p. 17734 - 17735
(2010/04/01)
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- COMPOSITION AND METHOD FOR THE TREATMENT OF CARCINOMA
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The present invention relates to compositions and methods useful for treating a carcinoma or viral infection in mammals, including humans. The methods and compositions typically comprise use of an immunogenic or immunomodulatory compound, and a γδT cell a
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Page/Page column 74-75
(2008/06/13)
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- Phosphalohydrins and methods for medicinal administration
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The invention provides compounds comprising at least one phosphohalohydrin group of the formula: where X is a halogen selected from among I, Br, Cl, R1 is selected from among —CH3and —CH2—CH3, Cat+ is an organic or inorgan
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Page column 16
(2008/06/13)
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- Tris(tetra-n-butylammonium) hydrogen pyrophosphate. A new reagent for the preparation of allylic pyrophosphate esters [3]
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Tris(tetra-n-butylammonium) hydrogen pyrophosphate was used to prepare dimethylallyl pyrophosphate (1-OPP), 7-methylocta-2,6-dien-1-yl pyrophosphate (2-OPP), geranyl pyrophosphate (3-OPP), 2-flourogeranyl pyrophosphate (4-OPP), and farnesyl pyrophosphate (5-OPP) from the corresponding alcohols in moderate yields by a two-step sequence via the corresponding primary, allylic bromides.
- Dixit, Vyas M.,Laskovics, F. Mark,Noall, Wendy I.,Poulter, C. Dale
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p. 1967 - 1969
(2007/10/02)
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