The D-glucosaminate dehydratase alpha-subunit from Pseudomonas fluorescens exhibits thioredoxin reductase activity.
The complete amino acid sequence of the D-glucosaminate dehydratase (GADH) alpha-subunit from Pseudomonas fluorescens was determined by PCR using genomic DNA from P. fluorescens as a template. The alpha-subunit comprises 320 amino acids and has a molecular mass of about 33.9 kDa. The primary structure of the alpha-subunit demonstrates a high similarity to the structures of thioredoxin reductase (TrxR) from many prokaryotes, especially Pseudomonas aeruginosa (identity 85%, positive 91%), Vibrio cholerae (identity 73%, positive 85%), and Escherichia coli (identity 71%, positive 83%). The purified glucosaminate dehydratase alpha(2)-enzyme exhibited NADPH-dependent TrxR activity, while TrxR from E. coli showed pyridoxal 5'-phosphate (PLP)-dependent GADH activity. The TrxR from E. coli suggests that there are three cofactor binding sites, FAD, NADPH, and PLP in the enzyme and that TrxR catalyzes the FAD- and NADPH-dependent oxidation-reduction reaction and the PLP-dependent alpha,beta-elimination reaction.
Iwamoto
Ryoko
R
Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan.
Amano
Chie
C
Ikehara
Kenji
K
Ushida
Naomi
N
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001483:Base Sequence; D006836:Hydro-Lyases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D021122:Protein Subunits; D011551:Pseudomonas fluorescens / Q000201:enzymology*; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism*
D001426:Bacterial Proteins; D021122:Protein Subunits; D013880:Thioredoxin-Disulfide Reductase; D006836:Hydro-Lyases; C018870:aminodeoxygluconate dehydratase