Regioselective para-Carboxylation of Catechols with a Prenylated Flavin Dependent Decarboxylase.

The utilization of CO 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 species.

Exploring the Catalytic Promiscuity of Phenolic Acid Decarboxylases: Asymmetric, 1,6-Conjugate Addition of Nucleophiles Across 4-Hydroxystyrene.

The catalytic promiscuity of a ferulic acid decarboxylase from sp. (FDC_s) 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% . The products obtained from the biotransformation employing the most suitable enzyme/nucleophile pairs were isolated and characterized after optimizing the reaction conditions.

Regioselective Enzymatic β-Carboxylation of -Hydroxy- styrene Derivatives Catalyzed by Phenolic Acid Decarboxylases.

We report on a 'green' method for the utilization of carbon dioxide as C unit for the regioselective synthesis of ()-cinnamic acids regioselective enzymatic carboxylation of -hydroxystyrenes. Phenolic acid decarboxylases from bacterial sources catalyzed the β-carboxylation of -hydroxystyrene derivatives with excellent regio- and (/)-stereoselectivity by exclusively acting at the β-carbon atom of the C=C side chain to furnish the corresponding ()-cinnamic acid derivatives in up to 40% conversion at the expense of bicarbonate as carbon dioxide source. Studies on the substrate scope of this strategy are presented and a catalytic mechanism is proposed based on molecular modelling studies supported by mutagenesis of amino acid residues in the active site.

Pushing the equilibrium of regio-complementary carboxylation of phenols and hydroxystyrene derivatives.

The enzymatic carboxylation of electron-rich aromatics, which represents a promising 'green' equivalent to the chemical Kolbe-Schmitt reaction, is thermodynamically disfavored and is therefore impeded by incomplete conversions. Optimization of the reaction conditions, such as pH, temperature, substrate concentration and the use of organic co-solvents and/or ionic liquids allowed to push the conversion in favor of carboxylation by a factor of up to 50%. Careful selection of the type of bicarbonate salt used as CO2 source was crucial to ensure optimal activities.

Interaction of the HIV-1 intasome with transportin 3 protein (TNPO3 or TRN-SR2).

Transportin 3 (TNPO3 or TRN-SR2) has been shown to be an important cellular factor for early steps of lentiviral replication. However, separate studies have implicated distinct mechanisms for TNPO3 either through its interaction with HIV-1 integrase or capsid. Here we have carried out a detailed biophysical characterization of TNPO3 and investigated its interactions with viral proteins.

Regioselective enzymatic carboxylation of phenols and hydroxystyrene derivatives.

The enzymatic carboxylation of phenol and styrene derivatives using (de)carboxylases in carbonate buffer proceeded in a highly regioselective fashion: Benzoic acid (de)carboxylases selectively formed o-hydroxybenzoic acid derivatives, phenolic acid (de)carboxylases selectively acted at the β-carbon atom of styrenes forming (E)-cinnamic acids.