Separation of<scp>l</scp>-Leucine-pyruvate and<scp>l</scp>-Leucine-α-ketoglutarate Transaminases in<i>Acetobacter suboxydans</i>and Identification of Their Reaction Products

Tachiki, Takashi; Tochikura, Tatsurokuro

doi:10.1080/00021369.1973.10860842

Cited by 4 publications

(1 citation statement)

References 3 publications

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“…These values of V max and K m point to the low affinity binding of L-Glu in the active site. This was observed earlier for other BCATs from P. aeruginosa and Gluconobacter oxydans (Norton and Sokatch, 1970; Tachiki and Tochikura, 1973; Kanda et al, 1995). For GEO1900 the extrapolated V max and K m values for pyruvate and AKG were (1.9 ± 0.1 U/mg and 10.6 ± 1.9 mM) and (18.2 ±1.2 U/mg and 1.9 ± 0.6 mM), respectively.…”

Section: Resultssupporting

confidence: 78%

Thermostable Branched-Chain Amino Acid Transaminases From the Archaea Geoglobus acetivorans and Archaeoglobus fulgidus: Biochemical and Structural Characterization

Isupov

Boyko

Sutter

et al. 2019

Front. Bioeng. Biotechnol.

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Two new thermophilic branched chain amino acid transaminases have been identified within the genomes of different hyper-thermophilic archaea, Geoglobus acetivorans, and Archaeoglobus fulgidus. These enzymes belong to the class IV of transaminases as defined by their structural fold. The enzymes have been cloned and over-expressed in Escherichia coli and the recombinant enzymes have been characterized both biochemically and structurally. Both enzymes showed high thermostability with optimal temperature for activity at 80 and 85°C, respectively. They retain good activity after exposure to 50% of the organic solvents, ethanol, methanol, DMSO and acetonitrile. The enzymes show a low activity to (R)-methylbenzylamine but no activity to (S)-methylbenzylamine. Both enzymes have been crystallized and their structures solved in the internal aldimine form, to 1.9 Å resolution for the Geoglobus enzyme and 2.0 Å for the Archaeoglobus enzyme. Also the Geoglobus enzyme structure has been determined in complex with the amino acceptor α-ketoglutarate and the Archaeoglobus enzyme in complex with the inhibitor gabaculine. These two complexes have helped to determine the conformation of the enzymes during enzymatic turnover and have increased understanding of their substrate specificity. A comparison has been made with another (R) selective class IV transaminase from the fungus Nectria haematococca which was previously studied in complex with gabaculine. The subtle structural differences between these enzymes has provided insight regarding their different substrate specificities.

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Section: Resultssupporting

confidence: 78%

Thermostable Branched-Chain Amino Acid Transaminases From the Archaea Geoglobus acetivorans and Archaeoglobus fulgidus: Biochemical and Structural Characterization

Isupov

Boyko

Sutter

et al. 2019

Front. Bioeng. Biotechnol.

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Branched-chain-amino-acid transaminase

Springer Handbook of Enzymes

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Structural Consideration of the Working Mechanism of Fold Type I Transaminases From Eubacteria: Overt and Covert Movement

Kwon

Park

2019

Computational and Structural Biotechnology Journal

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Transaminases (TAs) reversibly catalyze the transfer reaction of an amino group between an amino group donor and an amino group acceptor, using pyridoxal 5′-phosphate (PLP) as a cofactor. TAs are categorized according to the amino group position of the donor substrate and respective TAs recognize their own specific substrates. Over the past decade, a number of TA structures have been determined by X-ray crystallography. On the basis of the structural information, the detailed mechanism of substrate recognition by TAs has also been elucidated. In this review, fold type I TAs are addressed intensively. Comparative studies on structural differences between the apo and holo forms of fold type I TAs have demonstrated that regions containing the active site exhibit structural plasticity in the apo form, facilitating PLP insertion into the active site. In addition, given that TAs recognize two different kinds of substrates, they possess dual substrate specificity. It is known that spatial rearrangements of active site residues occur upon binding of the substrates. Intriguingly, positively charged residues are predominantly distributed at the active site cavity. The electric field generated by such charge distributions may attract negatively charged molecules, such as PLP and amino group acceptors, into the active site. Indeed, TAs show remarkable dynamics in diverse aspects. In this review, we describe the comprehensive working mechanism of fold type I TAs, with a focus on conformational changes.

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Separation ofl-Leucine-pyruvate andl-Leucine-α-ketoglutarate Transaminases inAcetobacter suboxydansand Identification of Their Reaction Products

Cited by 4 publications

References 3 publications

Thermostable Branched-Chain Amino Acid Transaminases From the Archaea Geoglobus acetivorans and Archaeoglobus fulgidus: Biochemical and Structural Characterization

Thermostable Branched-Chain Amino Acid Transaminases From the Archaea Geoglobus acetivorans and Archaeoglobus fulgidus: Biochemical and Structural Characterization

Branched-chain-amino-acid transaminase

Structural Consideration of the Working Mechanism of Fold Type I Transaminases From Eubacteria: Overt and Covert Movement

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