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A self-assembling evolutionary marvel . The Cellulosome. by: Drew Sowersby Supramolecular Chemistry 5390 Dr. Wendi David . Cellulose is the most abundant source of bioenergy on earth. BIOFUELS Applications. Rubin, E. Nature , 2008 , 454 , 841-845. The break down of cellulose
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A self-assembling evolutionary marvel The Cellulosome by: Drew Sowersby Supramolecular Chemistry 5390 Dr. Wendi David
Cellulose is the most abundant source of bioenergy on earth BIOFUELS Applications Rubin, E. Nature, 2008, 454, 841-845.
The break down of cellulose involves 2 major steps • Pretreatment • mechanical (shear) • chemical (ionic, dilute acids) • thermochemical (heat) • Hydrolysis • enzymatic (cellulases) • chemical (strong acids) switchgrass – before and after ionic liquid pretreatment Singh, S.; Simmons, B. a; Vogel, K. P. Biotechnology and bioengineering. 2009, 104, 68-75.
Hydrolysis to glucose is achieved via 3 enzymatic steps Graphic: Wikipedia
The Cellulosome Concept http://www.wzw.tum.de/mbiotec/celostruct.htm • Bayer and Lamed (1983) • Clostridium thermocellummost studied • extracellular molecular machine • molecular weight of over 2 MDa (2,000,000 Da) Lamed, R. et al. Biotechnol. Bioeng. Symp., 1983, 13, 163–18.
Characterization of the cellulosome Surface plasmon resonance Binding Isothermal calorimetry Recombinant DNA technology Composition Protein purification Complex crystallization Structure Bioinformatics and modeling Electron microscopy
What does the research say about the cellulosome? • Mechanism • Cellulosome self-assembly driven by non-specific • but highly complementary cohesin/dockerin interactions • Features • contains18 different dockerin containing enzymes • cellulases ranging in molecular weights of 40-180 kDa • dockerin is a 23-residue tandemly repeated sequence • dockerin contains 2 calcium binding loop-helix motifs • cooperative binding by carbohydrate binding modules (CBMs) • binding between dockerin and cohesin is species specific • cohesin is a 9-stranded β - sandwich with a jellyroll topology • Scaffoldin-cellulase superstructure results in synergistic cellulolytic • activity not seen with free floating cellulases • Shoham, Y.; Lamed, R.; Bayer, E.A. Trends Microbiol., 1999, 7, 275-281. • Schwarz, W. H. Appl. Microbiol. Biotechnol. 2001, 56, 634–649. • Pagès, S. et al. Proteins, 1997,29, 517–527. • Carvahlo, A. L. et al. PNAS, 2003, 100, 13809–13814.
Scaffoldin and the dockerin-cohesin complex scaffoldin
Polycellulosomal superstructures • extracellular construction • organismal monstrosity • resting vs. protracted • “Plasticity theory” • 1. Shoham, Y.; Lamed, R.; Bayer, E.A. Trends Microbiol., 1999, 7, 275-281. • 2. Bomble, Y. J. et al. J. Biol. Chem., 2011, 286, 5614-5623.
Video Simulation wrap-up • Bomble, Y. J. et al. J. Biol. Chem., 2011, 286, 5614-5623.