Design and production in Aspergillus niger of a chimeric protein associating a fungal feruloyl esterase and a clostridial dockerin domain

Appl Environ Microbiol. 2004 Dec;70(12):6984-91. doi: 10.1128/AEM.70.12.6984-6991.2004.

Abstract

A chimeric enzyme associating feruloyl esterase A (FAEA) from Aspergillus niger and dockerin from Clostridium thermocellum was produced in A. niger. A completely truncated form was produced when the dockerin domain was located downstream of the FAEA (FAEA-Doc), whereas no chimeric protein was produced when the bacterial dockerin domain was located upstream of the FAEA (Doc-FAEA). Northern blot analysis showed similar transcript levels for the two constructs, indicating a posttranscriptional bottleneck for Doc-FAEA production. The sequence encoding the first 514 amino acids from A. niger glucoamylase and a dibasic proteolytic processing site (kex-2) were fused upstream of the Doc-FAEA sequence. By using this fusion strategy, the esterase activity found in the extracellular medium was 20-fold-higher than that of the wild-type reference strain, and the production yield was estimated to be about 100 mg of chimeric protein/liter. Intracellular and extracellular production was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, dockerin-cohesin interaction assays, and Western blotting. Labeled cohesins detected an intact extracellular Doc-FAEA of about 43 kDa and a cleaved-off dockerin domain of about 8 kDa. In addition, an intracellular 120-kDa protein was recognized by using labeled cohesins and antibodies raised against FAEA. This protein corresponded to the unprocessed Doc-FAEA form fused to glucoamylase. In conclusion, these results indicated that translational fusion to glucoamylase improved the secretion efficiency of a chimeric Doc-FAEA protein and allowed production of the first functional fungal enzyme joined to a bacterial dockerin.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspergillus niger / enzymology*
  • Aspergillus niger / genetics
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Biotechnology / methods*
  • Carboxylic Ester Hydrolases / genetics
  • Carboxylic Ester Hydrolases / metabolism*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • Clostridium thermocellum / genetics
  • Clostridium thermocellum / metabolism*
  • Cohesins
  • Fungal Proteins
  • Nuclear Proteins / metabolism
  • Recombinant Fusion Proteins / metabolism*
  • Transcription, Genetic
  • Transformation, Genetic

Substances

  • Bacterial Proteins
  • Carrier Proteins
  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • Fungal Proteins
  • Nuclear Proteins
  • Recombinant Fusion Proteins
  • cellulose binding protein A, Clostridium cellulovorans
  • Carboxylic Ester Hydrolases
  • feruloyl esterase