Cloning, expression, and characterization of bacterial L-arabinose 1-dehydrogenase involved in an alternative pathway of L-arabinose metabolism

J Biol Chem. 2006 Feb 3;281(5):2612-23. doi: 10.1074/jbc.M506477200. Epub 2005 Dec 2.


Azospirillum brasiliense converts L-arabinose to alpha-ketoglutarate via five hypothetical enzymatic steps. We purified and characterized L-arabinose 1-dehydrogenase (EC, catalyzing the conversion of L-arabinose to L-arabino-gamma-lactone as an enzyme responsible for the first step of this alternative pathway of L-arabinose metabolism. The purified enzyme preferred NADP+ to NAD+ as a coenzyme. Kinetic analysis revealed that the enzyme had high catalytic efficiency for both L-arabinose and D-galactose. The gene encoding L-arabinose 1-dehydrogenase was cloned using a partial peptide sequence of the purified enzyme and was overexpressed in Escherichia coli as a fully active enzyme. The enzyme consists of 308 amino acids and has a calculated molecular mass of 33,663.92 Da. The deduced amino acid sequence had some similarity to glucose-fructose oxidoreductase, D-xylose 1-dehydrogenase, and D-galactose 1-dehydrogenase. Site-directed mutagenesis revealed that the enzyme possesses unique catalytic amino acid residues. Northern blot analysis showed that this gene was induced by L-arabinose but not by D-galactose. Furthermore, a disruptant of the L-arabinose 1-dehydrogenase gene did not grow on L-arabinose but grew on D-galactose at the same growth rate as the wild-type strain. There was a partial gene for L-arabinose transport in the flanking region of the L-arabinose 1-dehydrogenase gene. These results indicated that the enzyme is involved in the metabolism of L-arabinose but not D-galactose. This is the first identification of a gene involved in an alternative pathway of L-arabinose metabolism in bacterium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabinose / metabolism*
  • Arabinose / pharmacology
  • Azospirillum brasilense / enzymology
  • Bacterial Proteins
  • Carbohydrate Dehydrogenases / genetics
  • Carbohydrate Dehydrogenases / metabolism*
  • Catalytic Domain
  • Cloning, Molecular
  • Gene Expression Regulation* / drug effects
  • Glucose / metabolism
  • Kinetics
  • Molecular Sequence Data


  • Bacterial Proteins
  • Arabinose
  • Carbohydrate Dehydrogenases
  • L-arabinose dehydrogenase
  • Glucose

Associated data

  • GENBANK/AB211983