Structure of pyridoxal 5'-phosphate-bound D-threonine aldolase from Chlamydomonas reinhardtii.

D-Threonine aldolase (DTA) is a pyridoxal-5'-phosphate-dependent enzyme which catalyzes the reversible aldol reaction of glycine with a corresponding aldehyde to yield the D-form β-hydroxy-α-amino acid. This study produced and investigated the crystal structure of DTA from Chlamydomonas reinhardtii (CrDTA) at 1.85 Å resolution. To our knowledge, this is the first report on the crystal structure of eukaryotic DTA. Compared with the structure of bacterial DTA, CrDTA has a similar arrangement of active-site residues. On the other hand, we speculated that some non-conserved residues alter the affinity for substrates and inhibitors. The structure of CrDTA could provide insights into the structural framework for structure-guided protein engineering studies to modify reaction selectivity.