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- Hofer, Gerhard, et al.
(författare)
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Metal Ion Promiscuity and Structure of 2,3-Dihydroxybenzoic Acid Decarboxylase of Aspergillus oryzae
- 2021
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Ingår i: ChemBioChem. - : Wiley. - 1439-4227 .- 1439-7633. ; 22:4, s. 652-656
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Tidskriftsartikel (refereegranskat)abstract
- Broad substrate tolerance and excellent regioselectivity, as well as independence from sensitive cofactors have established benzoic acid decarboxylases from microbial sources as efficient biocatalysts. Robustness under process conditions makes them particularly attractive for preparative-scale applications. The divalent metal-dependent enzymes are capable of catalyzing the reversible non-oxidative (de)carboxylation of a variety of electron-rich (hetero)aromatic substrates analogously to the chemical Kolbe-Schmitt reaction. Elemental mass spectrometry supported by crystal structure elucidation and quantum chemical calculations verified the presence of a catalytically relevant Mg2+ complexed in the active site of 2,3-dihydroxybenoic acid decarboxylase from Aspergillus oryzae (2,3-DHBD_Ao). This unique example with respect to the nature of the metal is in contrast to mechanistically related decarboxylases, which generally have Zn2+ or Mn2+ as the catalytically active metal.
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- Leijondahl, Karin, 1978-
(författare)
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Synthesis and asymmetric transformations of diols by enzyme- and ruthenium catalysis
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The major part of this thesis describes the synthesis of aliphatic secondary diols and the development of lipase- and ruthenium-catalyzed asymmetric transformations of these diols. Several acyclic 1,4-diols and 1,5-diols were synthesized, and by combining a lipase-catalyzed asymmetric transformation with a ruthenium-catalyzed epimerization, enantiomerically- and diastereomerically enriched diacetates were obtained. The scope and limitations of the system were also investigated, and some problems were encountered with electron-deficient diols. The diacetate products were further transformed into natural product heterocycles and chiral ligands. A thorough study of the enzyme-catalyzed asymmetric transformation of 1,3-cyclohexanediol was also performed. It was found that there was a difference in the enzyme selectivity for the cis- and trans- diols, respectively, and while poor selectivity was observed for the trans-diol, cis-1,3-cyclohexanediol could be efficiently desymmetrized. By adding different epimerization catalysts, both cis- and trans-1,3-cyclohexanediol could be obtained in high enantio- and diastereoselectivities. The use of hydrogen transfer for the reduction of cyclic 1,3-diketones was also demonstrated, and the reactions could in many cases be carried out in a microwave oven.
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- Olsen, Jogvan Magnus Haugaard, et al.
(författare)
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Dalton Project : A Python platform for molecular- and electronic-structure simulations of complex systems
- 2020
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 152:21
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Tidskriftsartikel (refereegranskat)abstract
- The Dalton Project provides a uniform platform access to the underlying full-fledged quantum chemistry codes Dalton and LSDalton as well as the PyFraME package for automatized fragmentation and parameterization of complex molecular environments. The platform is written in Python and defines a means for library communication and interaction. Intermediate data such as integrals are exposed to the platform and made accessible to the user in the form of NumPy arrays, and the resulting data are extracted, analyzed, and visualized. Complex computational protocols that may, for instance, arise due to a need for environment fragmentation and configuration-space sampling of biochemical systems are readily assisted by the platform. The platform is designed to host additional software libraries and will serve as a hub for future modular software development efforts in the distributed Dalton community.
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- Payer, Stefan E., et al.
(författare)
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Exploring the Catalytic Promiscuity of Phenolic Acid Decarboxylases : Asymmetric, 1,6-Conjugate Addition of Nucleophiles Across 4-Hydroxystyrene
- 2017
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Ingår i: Advanced Synthesis and Catalysis. - : Wiley. - 1615-4150 .- 1615-4169. ; 359:12, s. 2066-2075
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Tidskriftsartikel (refereegranskat)abstract
- The catalytic promiscuity of a ferulic acid decarboxylase from Enterobacter sp. (FDC_Es) and phenolic acid decarboxylases (PADs) for the asymmetric conjugate addition of water across the C=C bond of hydroxystyrenes was extended to the N-, C-and S-nucleophiles methoxyamine, cyanide and propanethiol to furnish the corresponding addition products in up to 91% ee. The products obtained from the biotransformation employing the most suitable enzyme/nucleophile pairs were isolated and characterized after optimizing the reaction conditions. Finally, a mechanistic rationale supported by quantum mechanical calculations for the highly (S)selective addition of cyanide is proposed.
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| 8. |
- Payer, Stefan E., et al.
(författare)
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Regioselective para-Carboxylation of Catechols with a Prenylated Flavin Dependent Decarboxylase
- 2017
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 56:44, s. 13893-13897
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Tidskriftsartikel (refereegranskat)abstract
- The utilization of CO2 as a carbon source for organic synthesis meets the urgent demand for more sustainability in the production of chemicals. Herein, we report on the enzyme-catalyzed para-carboxylation of catechols, employing 3,4-dihydroxybenzoic acid decarboxylases (AroY) that belong to the UbiD enzyme family. Crystal structures and accompanying solution data confirmed that AroY utilizes the recently discovered prenylated FMN (prFMN) cofactor, and requires oxidative maturation to form the catalytically competent prFMN(iminium) species. This study reports on the in vitro reconstitution and activation of a prFMN-dependent enzyme that is capable of directly carboxylating aromatic catechol substrates under ambient conditions. A reaction mechanism for the reversible decarboxylation involving an intermediate with a single covalent bond between a quinoid adduct and cofactor is proposed, which is distinct from the mechanism of prFMN-associated 1,3-dipolar cycloadditions in related enzymes.
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- Sheng, Xiang, et al.
(författare)
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Reaction Mechanism and Substrate Specificity of Iso-orotate Decarboxylase : A Combined Theoretical and Experimental Study
- 2018
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The C-C bond cleavage catalyzed by metal-dependent iso-orotate decarboxylase (IDCase) from the thymidine salvage pathway is of interest for the elucidation of a (hypothetical) DNA demethylation pathway. IDCase appears also as a promising candidate for the synthetic regioselective carboxylation of N-heteroaromatics. Herein, we report a joint experimental-theoretical study to gain insights into the metal identity, reaction mechanism, and substrate specificity of IDCase. In contrast to previous assumptions, the enzyme is demonstrated by ICPMS/MS measurements to contain a catalytically relevant Mn(2+)rather than Zn2+. Quantum chemical calculations revealed that decarboxylation of the natural substrate (5-carboxyuracil) proceeds via a (reverse) electrophilic aromatic substitution with formation of CO2. The occurrence of previously proposed tetrahedral carboxylate intermediates with concomitant formation of HCO3- could be ruled out on the basis of prohibitively high energy barriers. In contrast to related o-benzoic acid decarboxylases, such as y-resorcylate decarboxylase and 5-carboxyvanillate decarboxylase, which exhibit a relaxed substrate tolerance for phenolic acids, IDCase shows high substrate fidelity. Structural and energy comparisons suggest that this is caused by a unique hydrogen bonding of the heterocyclic natural substrate (5-carboxyuracil) to the surrounding residues. Analysis of calculated energies also shows that the reverse carboxylation of uracil is impeded by a strongly disfavored uphill reaction.
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