The D-glucosaminate dehydratase alpha-subunit from Pseudomonas fluorescens exhibits thioredoxin reductase activity

Biochim Biophys Acta. 2003 Apr 11;1647(1-2):310-4. doi: 10.1016/s1570-9639(03)00079-7.

Abstract

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.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry*
  • Base Sequence
  • Hydro-Lyases / chemistry*
  • Hydro-Lyases / genetics
  • Hydro-Lyases / metabolism
  • Molecular Sequence Data
  • Protein Subunits
  • Pseudomonas fluorescens / enzymology*
  • Thioredoxin-Disulfide Reductase / metabolism*

Substances

  • Bacterial Proteins
  • Protein Subunits
  • Thioredoxin-Disulfide Reductase
  • Hydro-Lyases
  • aminodeoxygluconate dehydratase