Improvement in the Thermostability of a β‐Amino Acid Converting ω‐Transaminase by Using FoldX

Abstract ω‐Transaminases (ω‐TAs) are important biocatalysts for the synthesis of active, chiral pharmaceutical ingredients containing amino groups, such as β‐amino acids, which are important in peptidomimetics and as building blocks for drugs. However, the application of ω‐TAs is limited by the availability and stability of enzymes with high conversion rates. One strategy for the synthesis and optical resolution of β‐phenylalanine and other important aromatic β‐amino acids is biotransformation by utilizing an ω‐transaminase from Variovorax paradoxus . We designed variants of this ω‐TA to gain higher process stability on the basis of predictions calculated by using the FoldX software. We herein report the first thermostabilization of a nonthermostable S ‐selective ω‐TA by FoldX‐guided site‐directed mutagenesis. The melting point ( T m ) of our best‐performing mutant was increased to 59.3 °C, an increase of 4.0 °C relative to the T m value of the wild‐type enzyme, whereas the mutant fully retained its specific activity.