title: Creation of a broad-range and highly stereoselective D-amino acid dehydrogenase for the one-step synthesis of D-amino acids.
abstract: Using both rational and random mutagenesis, we have created the first known broad substrate range, nicotinamide cofactor dependent, and highly stereoselective d-amino acid dehydrogenase. This new enzyme is capable of producing d-amino acids via the reductive amination of the corresponding 2-keto acid with ammonia. This biocatalyst was the result of three rounds of mutagenesis and screening performed on the enzyme meso-diaminopimelate d-dehydrogenase. The first round targeted the active site of the wild-type enzyme and produced mutants that were no longer strictly dependent on the native substrate. The second and third rounds produced mutants that had an increased substrate range including straight- and branched-aliphatic amino acids and aromatic amino acids. The very high selectivity toward the d-enantiomer (95 to >99% ee) was shown to be preserved even after the addition of the five mutations found in the three rounds of mutagenesis and screening. This new enzyme could complement and improve upon current methods for d-amino acid synthesis.
authors.affiliation: BioCatalytics, Inc., 129 North Hill Avenue, Suite 103, Pasadena, California 91106, USA.
authors.forename: Kavitha
authors.initials: K
authors.lastname: Vedha-Peters
authors.forename: Manjula
authors.initials: M
authors.lastname: Gunawardana
authors.forename: J David
authors.initials: JD
authors.lastname: Rozzell
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Novick
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis*; D048230:Corynebacterium glutamicum / Q000201:enzymology; D003605:D-Amino-Acid Oxidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D009536:Niacinamide / Q000737:chemistry; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D009536:Niacinamide; D003605:D-Amino-Acid Oxidase