Effects of pH and temperature on (S)-amine activity of transaminase from the cold-adapted bacterium Psychrobacter cryohalolentis.

(7R,8S)-diaminopelargonic acid transaminase from the cold-adapted Gram-negative bacterium Psychrobacter cryohalolentis (Pcryo361) is able to react with unnatural substrates including (S)-( +)-1-phenylethylamine, aldehydes and α-diketones. Additionally, Pcryo361 is active at 0-50 °C and retains up to 10% of the maximum activity at 0 °C. Here, we report a detailed study on the stability and low temperature activity of Pcryo361.

Corrigendum: Thermostable Branched-Chain Amino Acid Transaminases From the Archaea and : Biochemical and Structural Characterization.

[This corrects the article DOI: 10.3389/fbioe.2019.

Thermostable Branched-Chain Amino Acid Transaminases From the Archaea and : Biochemical and Structural Characterization.

Two new thermophilic branched chain amino acid transaminases have been identified within the genomes of different hyper-thermophilic archaea, , and . These enzymes belong to the class IV of transaminases as defined by their structural fold. The enzymes have been cloned and over-expressed in and the recombinant enzymes have been characterized both biochemically and structurally.

Diaminopelargonic acid transaminase from Psychrobacter cryohalolentis is active towards (S)-(-)-1-phenylethylamine, aldehydes and α-diketones.

Substrate and reaction promiscuity is a remarkable property of some enzymes and facilitates the adaptation to new metabolic demands in the evolutionary process. Substrate promiscuity is also a basis for protein engineering for biocatalysis. However, molecular principles of enzyme promiscuity are not well understood.

Structural characterization of geranylgeranyl pyrophosphate synthase GACE1337 from the hyperthermophilic archaeon Geoglobus acetivorans.

A novel type 1 geranylgeranyl pyrophosphate synthase GACE1337 has been identified within the genome of a newly identified hyperthermophilic archaeon Geoglobus acetivorans. The enzyme has been cloned and over-expressed in Escherichia coli. The recombinant enzyme has been biochemically and structurally characterized.

A Novel highly thermostable branched-chain amino acid aminotransferase from the crenarchaeon Vulcanisaeta moutnovskia.

A new fold-type IV branched-chain amino acid aminotransferase VMUT0738 from the hyperthermophilic Crenarchaeon Vulcanisaeta moutnovskia was successfully expressed in Escherichia coli. Purified VMUT0738 showed activity toward numerous aliphatic and aromatic l-amino acids and 2-oxo acids at optimal pH 8.0.

Experimental and computational studies on the unusual substrate specificity of branched-chain amino acid aminotransferase from Thermoproteus uzoniensis.

PLP-Dependent fold-type IV branched-chain amino acid aminotransferases (BCATs) from archaea have so far been poorly characterized. A new BCAT from the hyperthermophilic archaeon Thermoproteus uzoniensis (TUZN1299) has been studied. TUZN1299 was found to be highly active toward branched-chain amino acids (BCAAs), positively charged amino acids, l-methionine, l-threonine, l-homoserine, l-glutamine, as well as toward 2-oxobutyrate and keto analogs of BCAAs, whereas l-glutamate and α-ketoglutarate were not converted in the overall reaction.

First structure of archaeal branched-chain amino acid aminotransferase from Thermoproteus uzoniensis specific for L-amino acids and R-amines.

The gene TUZN1299 from the genome of the hyperthermophilic archaeon Thermoproteus uzoniensis encoding a new 32.8 kDa branched-chain amino acid aminotransferase (BCAT) was expressed in Escherichia coli. The recombinant protein TUZN1299 was purified to homogeneity in the PLP-bound form.

Intramolecular hydrogen bonding in the polyextremophilic short-chain dehydrogenase from the archaeon Thermococcus sibiricus and its close structural homologs.

The short-chain alcohol dehydrogenase from the archaeon Thermococcus sibiricus (TsAdh319) exhibits adaptation to different kinds of stress: high temperature, high salinity, and the presence of organic solvents and denaturants. Previously a comparison of TsAdh319 with close structural homologs revealed an abnormally large number of charged residues on the surface of TsAdh319 tetramer. We further focused on the analysis of hydrogen bonding of TsAdh319 and its structural homologs from thermophilic and mesophilic organisms as a structural factor of adaptation to extreme environment.

Sodium chloride-induced modulation of the activity and thermal stability of short-chain oxidoreductase from the archaeon Thermococcus sibiricus.

Recently, we have studied properties and structural features of the thermostable halotolerant alcohol dehydrogenase from archaeon Thermococcus sibiricus (TsAdh319). In the present work, the effect of sodium chloride on activity and thermostability was explored using circular dichroism, fluorescent spectroscopy, and differential scanning calorimetry. The activity of TsAdh319 increased in the presence of NaCl and remained at the elevated level up to 4 M of NaCl.

Structural insight into the molecular basis of polyextremophilicity of short-chain alcohol dehydrogenase from the hyperthermophilic archaeon Thermococcus sibiricus.

Biochemical analysis of enantioselective short-chain alcohol dehydrogenase from the hyperthermophilic archaeon Thermococcus sibiricus (TsAdh319) revealed unique polyextremophilic properties of the enzyme - half-life of 1 h at 100 °C, tolerance to high salt (up to 4 M) and organic solvents (50% v/v) concentrations. To elucidate the molecular basis of TsAdh319 polyextremophilicity, we determined the crystal structure of the enzyme in a binary complex with 5-hydroxy-NADP at 1.68 Å resolution.

Characterization of a thermostable short-chain alcohol dehydrogenase from the hyperthermophilic archaeon Thermococcus sibiricus.

Short-chain alcohol dehydrogenase, encoded by the gene Tsib_0319 from the hyperthermophilic archaeon Thermococcus sibiricus, was expressed in Escherichia coli, purified and characterized as an NADPH-dependent enantioselective oxidoreductase with broad substrate specificity. The enzyme exhibits extremely high thermophilicity, thermostability, and tolerance to organic solvents and salts.