Expanding the L-Threonine Transaldolase Toolbox for the Diastereomeric Synthesis of Β-Hydroxy-Α-Amino Acids

•Three new L-threonine transaldolases (LTTAs) were mined and characterized.•The three LTTAs catalyze the synthesis of a variety of β‑hydroxy-α-amino acids.•The molecular mechanism of substrate specificity was revealed by molecular dynamics simulation.•L-Threo-p-methylsulfonyl phenylserine received a high yield (73.2%) and an excellent de value (85.9%) under optimal conditions.