High speed atomic force microscopy visualizes processive movement of Trichoderma reesei cellobiohydrolase I on crystalline cellulose

Kiyohiko Igarashi, Anu Koivula, Masahisa Wada, Satoshi Kimura, Merja Penttilä, Masahiro Samejima

Research output: Contribution to journalArticleScientificpeer-review

196 Citations (Scopus)

Abstract

Fungal cellobiohydrolases act at liquid-solid interfaces. They have the ability to hydrolyze cellulose chains of a crystalline substrate because of their two-domain structure, i.e. cellulose-binding domain and catalytic domain, and unique active site architecture. However, the details of the action of the two domains on crystalline cellulose are still unclear. Here, we present real time observations of Trichoderma reesei (Tr) cellobiohydrolase I (Cel7A) molecules sliding on crystalline cellulose, obtained with a high speed atomic force microscope. The average velocity of the sliding movement on crystalline cellulose was 3.5 nm/s, and interestingly, the catalytic domain without the cellulose-binding domain moved with a velocity similar to that of the intact TrCel7A enzyme. However, no sliding of a catalytically inactive enzyme (mutant E212Q) or a variant lacking tryptophan at the entrance of the active site tunnel (mutant W40A) could be detected. This indicates that, besides the hydrolysis of glycosidic bonds, the loading of a cellulose chain into the active site tunnel is also essential for the enzyme movement.

Original languageEnglish
Pages (from-to)36186-36190
JournalJournal of Biological Chemistry
Volume284
Issue number52
DOIs
Publication statusPublished - 25 Dec 2009
MoE publication typeA1 Journal article-refereed

Keywords

  • Trichoderma reesei
  • cellobiohydrolase
  • hydrolyzing
  • cellulose
  • cellulose hydrolysis
  • cellulose-binding domain
  • atomic force microscopy
  • high performance liquid chromatography (HPLC)
  • liquid chromatography

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