X-Ray crystal structure of the multidomain endoglucanase Cel9G from Clostridium cellulolyticum complexed with natural and synthetic cello-oligosaccharides

J Bacteriol. 2003 Jul;185(14):4127-35. doi: 10.1128/JB.185.14.4127-4135.2003.


Complete cellulose degradation is the first step in the use of biomass as a source of renewable energy. To this end, the engineering of novel cellulase activity, the activity responsible for the hydrolysis of the beta-1,4-glycosidic bonds in cellulose, is a topic of great interest. The high-resolution X-ray crystal structure of a multidomain endoglucanase from Clostridium cellulolyticum has been determined at a 1.6-A resolution. The endoglucanase, Cel9G, is comprised of a family 9 catalytic domain attached to a family III(c) cellulose-binding domain. The two domains together form a flat platform onto which crystalline cellulose is suggested to bind and be fed into the active-site cleft for endolytic hydrolysis. To further dissect the structural basis of cellulose binding and hydrolysis, the structures of Cel9G in the presence of cellobiose, cellotriose, and a DP-10 thio-oligosaccharide inhibitor were resolved at resolutions of 1.7, 1.8, and 1.9 A, respectively.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Cellobiose / metabolism
  • Cellulase / chemistry*
  • Cellulase / metabolism
  • Cellulose / metabolism*
  • Clostridium / enzymology*
  • Crystallization
  • Crystallography, X-Ray
  • Models, Molecular
  • Molecular Sequence Data
  • Oligosaccharides / metabolism*
  • Protein Conformation
  • Sequence Alignment


  • Oligosaccharides
  • Cellobiose
  • Cellulose
  • Cellulase

Associated data

  • PDB/ID1G87
  • PDB/ID1GA2
  • PDB/ID1K72