Tandem repeat of a seven-bladed beta-propeller domain in oligoxyloglucan reducing-end-specific cellobiohydrolase

Structure. 2004 Jul;12(7):1209-17. doi: 10.1016/j.str.2004.04.020.


Oligoxyloglucan reducing-end-specific cellobiohydrolase (OXG-RCBH; EC is an exoglucanase that recognizes the reducing end of oligoxyloglucan and releases two glucosyl residue segments from the main chain. The X-ray crystal structure of OXG-RCBH determined at 2.2 A resolution reveals a unique feature of this enzyme; OXG-RCBH consists of a tandem repeat of two similar domains, which are both folded into seven-bladed beta-propeller structures. The sequence alignment of the propeller blades, based on the structure, indicates that a weak repeat of the amino acid sequence occurred seven times to construct each domain. There is a cleft that can accommodate the substrate oligosaccharide between the two domains, which is a putative substrate binding subsite. Mutation of either Asp35 or Asp465, located in the putative catalytic center, to Asn resulted in a protein with no detectable catalytic activity, indicating the critical role of these amino acids in catalysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cellulose 1,4-beta-Cellobiosidase / chemistry*
  • Cellulose 1,4-beta-Cellobiosidase / metabolism
  • Crystallography, X-Ray
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Folding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Tandem Repeat Sequences


  • Cellulose 1,4-beta-Cellobiosidase

Associated data

  • PDB/1SQJ