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Title: Cellobiohydrolase 1 from Trichoderma reesei degrades cellulose in single cellobiose steps

Cellobiohydrolase 1 from Trichoderma reesei (TrCel7A) processively hydrolyses cellulose into cellobiose. Although enzymatic techniques have been established as promising tools in biofuel production, a clear understanding of the motor’s mechanistic action has yet to be revealed. We develop an optical tweezers-based single-molecule (SM) motility assay for precision tracking of TrCel7A. Direct observation of motility during degradation reveals processive runs and distinct steps on the scale of 1 nm. Our studies suggest TrCel7A is not mechanically limited, can work against 20 pN loads and speeds up when assisted. Temperature-dependent kinetic studies establish the energy requirements for the fundamental stepping cycle, which likely includes energy from glycosidic bonds and other sources. Moreover, through SM measurements of isolated TrCel7A domains, we determine that the catalytic domain alone is sufficient for processive motion, providing insight into TrCel7A’s molecular motility mechanism.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4]
  1. Vanderbilt Univ., Nashville, TN (United States)
  2. National Univ. of Singapore (Singapore)
  3. State Univ. of New Jersey, Piscataway, NJ (United States)
  4. Vanderbilt Univ., Nashville, TN (United States); National Univ. of Singapore (Singapore)
Publication Date:
OSTI Identifier:
1240602
Grant/Contract Number:
FC02-07ER64494
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Michigan State Univ., East Lansing, MI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES