The cellulose-binding domain of the major cellobiohydrolase of Trichoderma reesei exhibits true reversibility and a high exchange rate on crystalline cellulose

Markus Linder, Tuula T. Teeri

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Cellulose-binding domains (CBDs) bind specifically to cellulose, and form distinct domains of most cellulose degrading enzymes. The CBD-mediated binding of the enzyme has a fundamental role in the hydrolysis of the solid cellulose substrate. In this work we have investigated the reversibility and kinetics of the binding of the CBD from Trichoderma reesei cellobiohydrolase I on microcrystalline cellulose. The CBD was produced in Escherichia coli, purified, and radioactively labeled by reductive alkylation with H-3. Sensitive detection of the labeled CBD allowed more detailed analysis of its behavior than has been possible before, and important novel features were resolved. Binding of the CBD was found to be temperature sensitive, with an increased affinity at lower temperatures. The interaction of the CBD with cellulose was shown to be fully reversible and the CBD could be eluted from cellulose by simple dilution. The rate of exchange measured for the CBD-cellulose interaction compares well with the hydrolysis rate of cellobiohydrolase I, which is consistent with its proposed mode of action as a processive exoglucanase.

Original languageEnglish
Pages (from-to)12251-12255
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume93
Issue number22
DOIs
Publication statusPublished - 29 Oct 1996
MoE publication typeA1 Journal article-refereed

Keywords

  • cellulase
  • cellobiohydrolase I
  • protein adsorption
  • microcrystalline cellulose
  • NUCLEAR-MAGNETIC-RESONANCE
  • 2 CELLOBIOHYDROLASES
  • CARBOHYDRATE-BINDING
  • LIMITED PROTEOLYSIS
  • ADSORPTION
  • HYDROLYSIS
  • PROTEINS
  • CELLULASES

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