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 prFMNiminium 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.

The stereoselective addition of water across C = C bonds transforms prochiral alkenes to nonracemic alcohols and represents a major challenge in synthetic organic chemistry. In general, alkene hydration is an equilibrium reaction slightly favoring the alcohol side in 1,4-additions and somewhat disfavored on isolated C = C bonds. [1] Acid-catalyzed alkene hydration, which follows the rule of Markovnikov, usually proceeds with low regioselectivity and is often accompanied by rearrangement yielding regioisomeric product mixtures; with a few exceptions, [2] no generally applicable protocol has been developed so far. Likewise, base-catalyzed 1,4-addition of water to a,b-unsaturated (Michael) acceptors is impeded by the poor nucleophilicity of water. [3] Overall, an astonishingly limited number of asymmetric alkene-hydration protocols are reported: 1) The stereoselective hydration of a,b-unsaturated carboxylic acids by using a heterobimetallic chiral biopolymer (wool-Pd II -Co II ) catalyst furnished bhydroxy carboxylic acids in high optical purities, [4] and 2) the asymmetric syn-hydration of a,b-unsaturated acyl imidazoles while applying a DNA-based Cu II catalyst yielded b-hydroxy carbonyl compounds with moderate ee values. [5] To compensate for the insufficient nucleophilicity of water, indirect methods using strong nucleophiles (alkoxides, Nsilyloxycarbamates, oximes, silicon and boron reagents) have been employed, which require cumbersome reductive or oxidative follow-up chemistry to yield the desired b-hydroxy carbonyl compounds. [3]

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.In order to alleviate the predominant dependence of the chemical industry from petroleum-based platform intermediates, 1 the development of CO 2 -fixation reactions would allow conversion of a problematic waste gas into a useful carbon source for the production of chemicals. 2 The biggest obstacle to surmount is the low energy level of CO 2 . Carboxylation is facilitated by using high-energy starting materials, such as H 2 , organometallics, 3 unsaturated compounds (alkenes, alkynes, allenes 4 ), or epoxides. 5 Alternatively, carboxylation toward low-energy products containing carbon at a high oxidation state yields carbonates, carbamates, carboxylic acids, and esters or lactones.Although the number of processes based on chemical CO 2fixation is small, the volumes of production (e.g., urea, KolbeÀSchmitt reaction for phenol-carboxylation 6 ) are impressive. 7 Despite these isolated success stories, the use of CO 2 as raw material for organic synthesis is still heavily underdeveloped. 2,8 In this context, the biocatalytic CO 2fixation catalyzed by (de)carboxylases holds great potential. Analysis of biological CO 2 -fixation reveals that the major high-energy pathways 9 are more substrate-specific and thus are less likely to be adapted to non-natural organic compounds. 10 In contrast, detoxification pathways are more promising, because the removal of a multitude of toxins by a single broad-spectrum enzyme enhances the survival of the living system. Since carboxylation is a

Background: TNPO3 is a key cellular factor involved in early steps of HIV-1 replication. Results: TNPO3 is highly structured, interacts with the HIV-1 intasome by engaging the C-terminal domain of integrase, and does not directly bind capsid tubes. Conclusion: TNPO3 interacts with HIV-1 intasomes and not capsid cores. Significance: Our findings aid future genetic analysis to elucidate the role of TNPO3 in HIV-1 replication.

We report on a ‘green’ method for the utilization of carbon dioxide as C1 unit for the regioselective synthesis of (E)‐cinnamic acids via regioselective enzymatic carboxylation of para‐hydroxystyrenes. Phenolic acid decarboxylases from bacterial sources catalyzed the β‐carboxylation of para‐hydroxystyrene derivatives with excellent regio‐ and (E/Z)‐stereoselectivity by exclusively acting at the β‐carbon atom of the C=C side chain to furnish the corresponding (E)‐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. Permissions: WILEY-VCH

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More than one activity: Owing to their hydratase activity, phenolic acid decarboxylases catalyze the regio‐ and stereoselective addition of H2O across the CC double bond of hydroxystyrene derivatives yielding (S)‐4‐(1‐hydroxyethyl)phenols with up to 82 % conversion and 71 % ee. Based on structure analysis and molecular docking simulations, a catalytic mechanism for this novel enzymatic reaction is proposed.