Wednesday, May 6, 2009 - 4:00 PM
12-06

Single Molecule Tracking of Carbohydrate-Binding Modules Bound to Cellulose Crystals

Yu-San Liu1, Yining Zeng1, Yonghua Luo1, Qi Xu1, Michael E. Himmel1, Steve Smith2, and Shi-You Ding1. (1) Chemical and Biosciences Center, National Renewable Energy Laboratory, 1617 cole blvd, Golden, CO 80401, (2) Nano-Science & Engineering PhD Program, South Dakota School of Mines and Technology, 501 East St. Joseph Street, Rapid City, SD 57701

To develop more cost-effective approaches to liberate fermentable sugars from recalcitrant biomass, the enzyme cocktail used for saccharification must be improved. We have developed a single-molecule technique based on fluorescence imaging to track the motion of cellulase components with spatial resolution at several nanometers.  We used single molecule spectroscopy to study the behavior of carbohydrate-binding modules (CBMs) labeled with quantum dots (QDs) while bound to cellulose crystals.  These bio-assembles were subjected to total internal reflection fluorescence (TIRF) microscopy.  The concentrations of the CBMs and QDs were optimized to achieve single molecule resolution. This technique revealed a confined nanometer-scale movement of the CBMs bound to cellulose. Although the mechanism of CBM motion is still unknown, the single molecule approach used here offers new opportunities to guide us toward a fundamental understanding of cellulase function, especially the mechanism of the “processivity” of exoglucanse.

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See more of The 31st Symposium on Biotechnology for Fuels and Chemicals (May 3-6, 2009)