From Structure to Function: Analysis of the First Monomeric Pyridoxal-5'-Phosphate-Dependent Transaminase from the Bacterium .

The first monomeric pyridoxal-5'-phosphate (PLP)-dependent transaminase from a marine, aromatic-compound-degrading, sulfate-reducing bacterium Tol2, has been studied using structural, kinetic, and spectral methods. The monomeric organization of the transaminase was confirmed by both gel filtration and crystallography. The PLP-dependent transaminase is of the fold type IV and deaminates D-alanine and ()-phenylethylamine in half-reactions.

Insights into the Functioning of the D-amino Acid Transaminase from Haliscomenobacter Hydrossis via a Structural and Spectral Analysis of its Complex with 3-Aminooxypropionic Acid.

Pyridoxal 5'-phosphate-dependent enzymes play a crucial role in nitrogen metabolism. Carbonyl compounds, such as O-substituted hydroxylamines, stand out among numerous specific inhibitors of these enzymes, including those of practical importance, because they react with pyridoxal 5'-phosphate in the active site of the enzymes to form stable oximes. O-substituted hydroxylamines mimic the side group of amino acid substrates, thus providing highly potent and specific inhibition of the corresponding enzymes.

Incorporation of pyridoxal-5'-phosphate into the apoenzyme: A structural study of D-amino acid transaminase from Haliscomenobacter hydrossis.

Pyridoxal-5'-phosphate (PLP)-dependent transaminases are key enzymes of amino acid metabolism in cells and remarkable biocatalysts of stereoselective amination for process chemistry applications. As cofactor-dependent enzymes, transaminases are prone to cofactor leakage. Here we discuss the holoenzyme-apoenzyme interconversion and the kinetics of PLP incorporation into the apo form of a PLP-dependent transaminase from Haliscomenobacter hydrossis.

Multifunctionality of arginine residues in the active sites of non-canonical d-amino acid transaminases.

Structure-function relationships are key to understanding enzyme mechanisms, controlling enzyme activities, and designing biocatalysts. Here, we investigate the functions of arginine residues in the active sites of pyridoxal-5'-phosphate (PLP)-dependent non-canonical d-amino acid transaminases, focusing on the analysis of a transaminase from Haliscomenobacter hydrossis. Our results show that the tandem of arginine residues R28* and R90, which form the conserved R-[RK] motif in non-canonical d-amino acid transaminases, not only facilitates effective substrate binding but also regulates the catalytic properties of PLP.

Expanded Substrate Specificity in D-Amino Acid Transaminases: A Case Study of Transaminase from .

Enzymes with expanded substrate specificity are good starting points for the design of biocatalysts for target reactions. However, the structural basis of the expanded substrate specificity is still elusive, especially in the superfamily of pyridoxal-5'-phosphate-dependent transaminases, which are characterized by a conserved organization of both the active site and functional dimer. Here, we analyze the structure-function relationships in a non-canonical D-amino acid transaminase from , which is active towards D-amino acids and primary ()-amines.