Biocatalysis of carboxylic acid reductases: phylogenesis, catalytic mechanism and potential applications

Qu, Ge; Guo, Jinggong; Yang, Dameng; Sun, Zhoutong

doi:10.1039/c7gc03046k

Cited by 61 publications

(36 citation statements)

References 116 publications

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“…The carboxylic acid reductases (CARs) are enzymes that have increasing interest as biocatalysts . CARs catalyze the reduction of carboxylic acids to aldehydes in mild conditions, and can connect many types of enzyme reaction allowing the construction of novel multi‐enzyme pathways (Figure A) .…”

Section: Introductionmentioning

confidence: 99%

Engineering a Seven Enzyme Biotransformation using Mathematical Modelling and Characterized Enzyme Parts

et al. 2019

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Multi‐step enzyme reactions offer considerable cost and productivity benefits. Process models offer a route to understanding the complexity of these reactions, and allow for their optimization. Despite the increasing prevalence of multi‐step biotransformations, there are few examples of process models for enzyme reactions. From a toolbox of characterized enzyme parts, we demonstrate the construction of a process model for a seven enzyme, three step biotransformation using isolated enzymes. Enzymes for cofactor regeneration were employed to make this in vitro reaction economical. Good modelling practice was critical in evaluating the impact of approximations and experimental error. We show that the use and validation of process models was instrumental in realizing and removing process bottlenecks, identifying divergent behavior, and for the optimization of the entire reaction using a genetic algorithm. We validated the optimized reaction to demonstrate that complex multi‐step reactions with cofactor recycling involving at least seven enzymes can be reliably modelled and optimized.

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Section: Introductionmentioning

confidence: 99%

Engineering a Seven Enzyme Biotransformation using Mathematical Modelling and Characterized Enzyme Parts

et al. 2019

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“…Recent studies have also highlighted the use of a CAR from Mycobacterium marinum for the biosynthesis of alkanes as biofuel, due to its appreciable activity on C 4 –C 18 fatty acids . Additional examples of incorporating CAR activities into (bio)syntheses were recently reviewed …”

Section: Introductionmentioning

confidence: 99%

Characterization of Carboxylic Acid Reductases for Biocatalytic Synthesis of Industrial Chemicals

et al. 2018

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Carboxylic acid reductases (CARs) catalyze the reduction of a broad range of carboxylic acids into aldehydes, which can serve as common biosynthetic precursors to many industrial chemicals. This work presents the systematic biochemical characterization of five carboxylic acid reductases from different microorganisms, including two known and three new ones, by using a panel of short-chain dicarboxylic acids and hydroxy acids, which are common cellular metabolites. All enzymes displayed broad substrate specificities. Higher catalytic efficiencies were observed when the carbon chain length, either of the dicarboxylates or of the terminal hydroxy acids, was increased from C to C . In addition, when substrates of the same carbon chain length are compared, carboxylic acid reductases favor hydroxy acids over dicarboxylates as their substrates. Whole-cell bioconversions of eleven carboxylic acid substrates into the corresponding alcohols were investigated by coupling the CAR activity with that of an aldehyde reductase in Escherichia coli hosts. Alcohol products were obtained in yields ranging from 0.5 % to 71 %. The de novo stereospecific biosynthesis of propane-1,2-diol enantiomer was successfully demonstrated with use of CARs as the key pathway enzymes. E. coli strains accumulated 7.0 mm (R)-1,2-PDO (1.0 % yield) or 9.6 mm (S)-1,2-PDO (1.4 % yield) from glucose. This study consolidates carboxylic acid reductases as promising enzymes for sustainable synthesis of industrial chemicals.

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“…A detailed list can be found in SI Table S1. A phylogenetic analysis revealed that all 30 experimentally confirmed bacterial CARs are categorized as subtype I and seemed to be relatively conserved, whereas the 4 fungal CARs with very low sequence identities (<25 %) fall into three distinct subclasses . The activity of fungal CAR from the ascomycete Neurospora crassa was described in 1968 by Gross et al .…”

Section: Introductionmentioning

confidence: 99%

“…A phylogenetic analysis revealed that all 30 experimentally confirmed bacterial CARs are categorized as subtype I and seemed to be relatively conserved, whereas the 4 fungal CARs with very low sequence identities (< 25 %) fall into three distinct subclasses. [11,12] The activity of fungal CAR from the ascomycete Neurospora crassa was described in 1968 by Gross et al [13] In 2016, the gene sequence was associated to the protein and cloned into E. coli with an additional phosphopantetheinyl transferase from E. coli. [14] Like other CARs, [15] Neurospora crassa CAR (NcCAR) requires the co-expression of a phosphopantetheinyl transferase.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Type IV Carboxylate Reductases (CARs) for Whole Cell‐Mediated Preparation of 3‐Hydroxytyrosol

et al. 2019

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Fragrance and flavor industries could not imagine business without aldehydes. Processes for their commercial production raise environmental and ecological concerns. The chemical reduction of organic acids to aldehydes is challenging. To fulfill the demand of a mild and selective reduction of carboxylic acids to aldehydes, carboxylic acid reductases (CARs) are gaining importance. We identified two new subtype IV fungal CARs from Dichomitus squalens CAR (DsCAR) and Trametes versicolor CAR (Tv2CAR) in addition to literature known Trametes versicolor CAR (TvCAR). Expression levels were improved by the co‐expression of GroEL‐GroES with either the trigger factor or the DnaJ‐DnaK‐GrpE system. Investigation of the substrate scope of the three enzymes revealed overlapping substrate‐specificities. Tv2CAR and DsCAR showed a preferred pH range of 7.0 to 8.0 in bicine buffer. TvCAR showed highest activity at pH 6.5 to 7.5 in MES buffer and slightly reduced activity at pH 6.0 or 8.0. TvCAR appeared to tolerate a wider pH range without significant loss of activity. Type IV fungal CARs optimal temperature was in the range of 25–35 °C. TvCAR showed a melting temperature (Tm) of 55 °C indicating higher stability compared to type III and the other type IV fungal CARs (Tm 51–52 °C). Finally, TvCAR was used as the key enzyme for the bioreduction of 3,4‐dihydroxyphenylacetic acid to the antioxidant 3‐hydroxytyrosol (3‐HT) and gave 58 mM of 3‐HT after 24 h, which correlates to a productivity of 0.37 g L−1 h−1.

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Biocatalysis of carboxylic acid reductases: phylogenesis, catalytic mechanism and potential applications

Abstract: Recent advances in carboxylic acid reductases and their practical applications in bio-cascade processes.

Cited by 61 publications

References 116 publications

Engineering a Seven Enzyme Biotransformation using Mathematical Modelling and Characterized Enzyme Parts

Engineering a Seven Enzyme Biotransformation using Mathematical Modelling and Characterized Enzyme Parts

Characterization of Carboxylic Acid Reductases for Biocatalytic Synthesis of Industrial Chemicals

Characterization of Type IV Carboxylate Reductases (CARs) for Whole Cell‐Mediated Preparation of 3‐Hydroxytyrosol

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