Stereoelectronic effects in the reaction of aromatic substrates catalysed by Halomonas elongata transaminase and its mutants

Contente, Martina Letizia; Planchestainer, Matteo; Molinari, Francesco; Paradisi, Francesca

doi:10.1039/c6ob01629d

Cited by 10 publications

(6 citation statements)

References 22 publications

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“…Therefore, the VbT A sequence was further analysed to gain insight into its structure and lack of solubility. Previous structural studies, whereby the active site of a He TA homology model was probed by site directed mutagenesis to investigate the enzyme affinity for specific aromatic substrates 24 , highlighted that F18 (corresponding to T16 in VbT A) is a key active site residue in the catalytic pocket. It forms a strong interaction with a second phenylalanine (F84, contributed by the second monomer), thus stabilizing the compact dimeric structure.…”

Section: Resultsmentioning

confidence: 99%

Strategic single point mutation yields a solvent- and salt-stable transaminase from Virgibacillus sp. in soluble form

Guidi

Planchestainer

Contente

et al. 2018

Sci Rep

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A new transaminase (VbTA) was identified from the genome of the halotolerant marine bacterium Virgibacillus 21D. Following heterologous expression in Escherichia coli, it was located entirely in the insoluble fraction. After a single mutation, identified via sequence homology analyses, the VbTA T16F mutant was successfully expressed in soluble form and characterised. VbTA T16F showed high stability towards polar organic solvents and salt exposure, accepting mainly hydrophobic aromatic amine and carbonyl substrates. The 2.0 Å resolution crystal structure of VbTA T16F is here reported, and together with computational calculations, revealed that this mutation is crucial for correct dimerisation and thus correct folding, leading to soluble protein expression.

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Section: Resultsmentioning

confidence: 99%

Strategic single point mutation yields a solvent- and salt-stable transaminase from Virgibacillus sp. in soluble form

Guidi

Planchestainer

Contente

et al. 2018

Sci Rep

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“…To the best of our knowledge, there are only a few reports dealing with the acceptance of halogenated ketones by amine transaminases . For instance, Slabu et al., Cassimjee et al., and Paul et al .…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Synthesis of Chiral Halogenated Amines using Amine Transaminases

2018

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Amine transaminases (ATAs) are versatile and industrially relevant biocatalysts that catalyze the transfer of an amine group from a donor to an acceptor molecule. Asymmetric synthesis from a prochiral ketone is the most preferred route to the desired amine product, as it is obtainable in a theoretical yield of 100 %. In addition to the requirement of active and enantioselective ATAs, the choice of a suitable amine donor is also important to save costs and to avoid additional enzymes to shift the equilibrium and/or to recycle the cofactors. In this work, we identified suitable (R)‐ and (S)‐ATAs from Aspergillus fumigatus and Silicibacter pomeroyi, respectively, to afford a set of halogen‐substituted derivatives of brominated or chlorinated 1‐phenyl‐2‐propanamine, 4‐phenylbutan‐2‐amine, and 1‐(3‐pyridinyl)ethanamine. Optimization of the donor–acceptor ratio enabled application of isopropylamine as an amine donor, which resulted in high conversions and amines with 73–99 % ee.

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“…This enzyme showed a broad substrate scope and a high tolerance to a variety of organic co-solvents (e.g., methanol, ethanol, DMSO, isopropanol) up to 20% (Cerioli et al 2015). Harnessing these properties that other homologous transaminases do not possess, HewT has been extensively exploited for the synthesis of high-value molecules in pharmaceutical synthesis (Contente and Paradisi 2018;Cairns et al 2019;Contente et al 2019;Hegarty and Paradisi 2020;Roura Padrosa et al 2020;Heckmann et al 2021;Romero-Fernandez and Paradisi 2021), polymer chemistry (Romero-Fernandez et al 2022), food chemistry (Planchestainer et al 2017;Benítez-Mateos et al 2018Roura Padrosa et al 2021), and other applications (Contente et al 2016;Planchestainer et al 2019;Czarnievicz et al 2022).…”

Section: Transferasesmentioning

confidence: 99%

Halomonas elongata: a microbial source of highly stable enzymes for applied biotechnology

Benítez‐Mateos

Paradisi

2023

Appl Microbiol Biotechnol

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Extremophilic microorganisms, which are resistant to extreme levels of temperature, salinity, pH, etc., have become popular tools for biotechnological applications. Due to their availability and cost-efficacy, enzymes from extremophiles are getting the attention of researchers and industries in the field of biocatalysis to catalyze diverse chemical reactions in a selective and sustainable manner. In this mini-review, we discuss the advantages of Halomonas elongata as moderate halophilic bacteria to provide suitable enzymes for biotechnology. While enzymes from H. elongata are more resistant to the presence of salt compared to their mesophilic counterparts, they are also easier to produce in heterologous hosts compared with more extremophilic microorganisms. Herein, a set of different enzymes (hydrolases, transferases, and oxidoreductases) from H. elongata are showcased, highlighting their interesting properties as more efficient and sustainable biocatalysts. With this, we aim to improve the visibility of halotolerant enzymes and their uncommon properties to integrate biocatalysis in industrial set-ups. Keypoints • Production and use of halotolerant enzymes can be easier than strong halophilic ones. • Enzymes from halotolerant organisms are robust catalysts under harsh conditions. • Halomonas elongata has shown a broad enzyme toolbox with biotechnology applications.

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Stereoelectronic effects in the reaction of aromatic substrates catalysed by Halomonas elongata transaminase and its mutants

Cited by 10 publications

References 22 publications

Strategic single point mutation yields a solvent- and salt-stable transaminase from Virgibacillus sp. in soluble form

Strategic single point mutation yields a solvent- and salt-stable transaminase from Virgibacillus sp. in soluble form

Asymmetric Synthesis of Chiral Halogenated Amines using Amine Transaminases

Halomonas elongata: a microbial source of highly stable enzymes for applied biotechnology

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