Cloning and sequence analysis of the gene for glucodextranase from Arthrobacter globiformis T-3044 and expression in Escherichia coli cells

Biosci Biotechnol Biochem. 1999 Dec;63(12):2174-82. doi: 10.1271/bbb.63.2174.

Abstract

The gld gene for glucodextranase from Arthrobacter globiformis T-3044 was cloned by using a combination of gene walking and probe methods and expressed on the recombinant plasmid pGD8, which was constructed with pUC118, in Escherichia coli cells. The enzyme gene consisted of a unique open reading frame of 3,153 bp. The comparison of the DNA sequence data with the N-terminal and 6 internal amino acid sequences of the purified enzyme secreted from A. globiformis T-3044 suggested the enzyme was translated from mRNA as a secretory precursor with a signal peptide of 28 amino acids residues. The deduced amino acids sequence of the mature enzyme contained 1,023 residues, resulting in a polypeptide with a molecular mass of 107,475 daltons. The deduced sequence showed about 38% identity to that of the glucoamylase from Clostridium sp. G0005. The glucodextranase activity of transformant harboring pGD8 was about 40 mU/ml at 30 degrees C for a 16-h culture. Although the GDase that was produced from the transformant was shorter than authentic GDase by 2 amino acid residues at the N-terminal end side, its enzymatic properties were almost same as the authentic one. Two kinds of genes, dex1 and dex2, for endo-dextranases from A. globiformis T-3044 were also cloned into Escherichia coli cells. The N-terminal of the purified endo-dextranase from A. globiformis T-3044 agreed with the deduced amino acid sequence, after the 33rd alanine residue, of only the dex1 gene for edo-dextranase. This result suggests that the endo-dextranase is translated from mRNA as a secretory precursor with a signal peptide of 32 amino acids residues. The deduced sequence of endo-dextranase 1 and endo-dextranase 2 showed about 93% and 65% identity with that of known endo-dextranase from Arthrobacter sp. CB-8, respectively.

MeSH terms

  • Amino Acid Sequence
  • Arthrobacter / enzymology*
  • Base Sequence
  • Cloning, Molecular
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / enzymology*
  • Gene Expression Regulation, Enzymologic
  • Glucosidases / genetics*
  • Molecular Sequence Data
  • Plasmids
  • Polymerase Chain Reaction
  • Restriction Mapping

Substances

  • Glucosidases
  • exo-1,6-alpha-glucosidase