| 초록 |
Engineering D-lactic acid dehydrogenases for higher activity on diverse 2-oxo acids is necessary for the synthesis of 2-hydroxy acids. The application of 2-hydroxy acids includes biopolymers, pharmaceuticals and cosmetic compounds. Although there are many D-lactate dehydrogenases (DLDH) from various origins, they have low activities for 2-oxo acids with large functional group at C3. In this study, the D-LDH from Pediococcus acidilactici was rationally designed by modulating the intermolecular interactions between the substrates and the residues in the active site. As a result, Y51L mutant with the catalytic ability on phenylpyruvate of 2200 s-1 mM-1 and Y51F mutant on 2-oxobutryate and 3-methyl-2-oxobutyrate of 37.2 and 23.2 s-1 mM-1, were found, which were 138-, 8.5-, and 26-fold higher than the wild type, respectively. Structural analysis explained that the distance and the properties of the interactions between the side chain of the residue 51 and the substrate C3 substituent group were related with the kinetic parameters. |
