title: A new D-2-hydroxyacid dehydrogenase with dual coenzyme-specificity from Haloferax mediterranei, sequence analysis and heterologous overexpression.
abstract: A gene encoding a new D-2-hydroxyacid dehydrogenase (E.C. 1.1.1.) from the halophilic Archaeon Haloferax mediterranei has been sequenced, cloned and expressed in Escherichia coli cells with the inducible expression plasmid pET3a. The nucleotide sequence analysis showed an open reading frame of 927 bp which encodes a 308 amino acid protein. Multiple amino acid sequence alignments of the D-2-hydroxyacid dehydrogenase from H. mediterranei showed high homology with D-2-hydroxyacid dehydrogenases from different organisms and other enzymes of this family. Analysis of the amino acid sequence showed catalytic residues conserved in hydroxyacid dehydrogenases with d-stereospecificity. In the reductive reaction, the enzyme showed broad substrate specificity, although alpha-ketoisoleucine was the most favourable of all alpha-ketocarboxylic acids tested. Kinetic data revealed that this new D-2-hydroxyacid dehydrogenase from H. mediterranei exhibits dual coenzyme-specificity, using both NADPH and NADH as coenzymes. To date, all D-2-hydroxyacid dehydrogenases have been found to be NADH-dependent. Here, we report the first example of a D-2-hydroxyacid dehydrogenase with dual coenzyme-specificity.
authors.affiliation: Departamento de Agroquímica y Bioquímica, Division de Bioquímica, Facultad de Ciencias, Universidad de Alicante, Ap. 99, 03080 Alicante, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Domenech
authors.forename: J
authors.initials: J
authors.lastname: Ferrer
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D003067:Coenzymes / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D019623:Haloferax mediterranei / Q000201:enzymology* / Q000235:genetics*; D007700:Kinetics; D008969:Molecular Sequence Data; D017510:Protein Folding; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017421:Sequence Analysis; D013379:Substrate Specificity
chemical_list: D019843:Archaeal Proteins; D003067:Coenzymes; D011994:Recombinant Proteins; D000429:Alcohol Oxidoreductases; C021379:D-2-hydroxyacid dehydrogenase