Form Submission: News & Articles

Author: 

Erica T. Prates and Munir S. Skaf

Author's email: 

ericatprates@gmail.com

News Type: 

Small-angle X-ray experiments reveal that the studied β-glucosidase from Aspergillus niger (AnBgl1) has a tadpole-like structure,a molecular organization resembles the one adopted by other cellulases that frequently contain catalytic domain linked to the cellulose binding module which mediate their binding to insoluble and polymeric cellulose. The reasons why AnBgl1, which acts on the small soluble substrates, has a tadpole molecular shape are not entirely clear. Molecular dynamics simulations suggested that clusters of residues located in the C-terminal FnIII domain interact strongly with lignin fragments. These results indicate that C-terminal FnIII domain could be operational for immobilization of the enzyme on the cell-wall and for preventing of cellulase unproductive binding to the biomass lignin.
Aspergillus niger beta-glucosidase has a cellulase-like tadpole molecular shape: insights into GH3 beta-glucosidases structure and function

Full Article URL: 

Aspergillus niger is known to secrete large amounts of β-glucosidases, which have a variety of biotechnological and industrial applications. Here, we purified an A. niger β-glucosidase (AnBgl1) and conducted its biochemical and biophysical analyses. Surprisingly, the small-angle X-ray experiments reveal that AnBgl1 has a tadpole-like structure, with the N-terminal catalytic domain and C-terminal fibronectin III-like domain (FnIII) connected by the long linker peptide in an extended conformation. This molecular organization resembles the one adopted by other cellulases that frequently contain catalytic domain linked to the cellulose binding module which mediate their binding to insoluble and polymeric cellulose. The reasons why AnBgl1, which acts on the small soluble substrates, has a tadpole molecular shape are not entirely clear. However, our enzyme pull-down assays with different polymeric substrates suggest that AnBgl1 has little or no capacity to bind to and to adsorb on cellulose, xylan and starch, but has high affinity to lignin. Molecular dynamics simulations suggested that clusters of residues located in the C-terminal FnIII domain interact strongly with lignin fragments. The simulations showed that numerous arginine residues scattered throughout the FnIII surface play an important role in the interaction with lignin by means of cation-π stacking with the lignin aromatic rings. These results indicate that C-terminal FnIII domain could be operational for immobilization of the enzyme on the cell-wall and for preventing of cellulase unproductive binding to the biomass lignin.

Zircon - This is a contributing Drupal Theme
Design by WeebPal.