Identification and functional characterization of NAD(P)+ ‐dependent meso‐diaminopimelate dehydrogenase from Numidum massiliense

We report the identification and functional characterization of a novel NAD(P)+‐dependentmeso‐DAPDH fromNumidum massiliense (NmDAPDH). The knownmeso‐DAPDHs use only NADP+ as a coenzyme, but NmDAPDH was able to use both NADP+ and NAD+ as coenzymes. Abstractmeso‐Diaminopimelate dehydrogenase (meso‐DAPDH) catalyzes the reversible NADP+‐dependent oxidative deamination ofmeso‐2,6‐diaminopimelate (meso‐DAP) to producel‐2‐amino‐6‐oxopimelate. Moreover,d‐amino acid dehydrogenase (d‐AADHs) derived from protein‐engineeredmeso‐DAPDH is useful for one‐step synthesis ofd‐amino acids with high optical purity. Here, we report the identification and functional characterization of a novel NAD(P)+‐dependentmeso‐DAPDH fromNumidum massiliense (NmDAPDH). After the gene encoding the putative NmDAPDH was expressed in recombinantEscherichia coli cells, the enzyme was purified 4.0 ‐fold to homogeneity from the crude extract through five purification steps. Although the previously knownmeso‐DAPDHs use only NADP+ as a coenzyme, NmDAPDH was able to use both NADP+ and NAD+ as coenzymes. When NADP+ was used as a coenzyme, NmDAPDH exhibited an approximately 2 times higherkcat/Km value towardmeso‐DAP than that ofmeso‐DAPDH fromSymbiobacterium thermophilum (StDAPDH). NmDAPDH also catalyzed the reductive amination of corresponding 2 ‐oxo acids to produce acidicd‐amino acids such asd‐aspartate andd‐glutamate. The optimum pH and temperature for the oxida...

Source: MicrobiologyOpen - June 1, 2020 Category: Microbiology Authors: Hironaga Akita, Yusuke Nakamichi, Tomotake Morita, Akinori Matsushika Tags: ORIGINAL ARTICLE Source Type: research