The Cellulosome
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Transcript of The Cellulosome
THE CELLULOSOMEA self-assembling evolutionary marvel
by: Drew Sowersby
Supramolecular Chemistry 5390Dr. Wendi David
Cellulose is the most abundant source of bioenergy on earth
Rubin, E. Nature, 2008, 454, 841-845.
BIOFUELSApplications
Singh, S.; Simmons, B. a; Vogel, K. P. Biotechnology and bioengineering. 2009, 104, 68-75.
The break down of celluloseinvolves 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
Graphic: Wikipedia
Hydrolysis to glucose isachieved via 3 enzymatic steps
http://www.wzw.tum.de/mbiotec/celostruct.htm
The Cellulosome Concept
Bayer and Lamed (1983) Clostridium thermocellum most 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
Complex crystallization
Isothermal calorimetry
Protein purification
Recombinant DNA technology
Bioinformatics and modeling
Electron microscopy
Surface plasmon resonance
Binding
Structure
Composition
What does the research sayabout the cellulosome?
1. Shoham, Y.; Lamed, R.; Bayer, E.A. Trends Microbiol., 1999, 7, 275-281.2. Schwarz, W. H. Appl. Microbiol. Biotechnol. 2001, 56, 634–649.3. Pagès, S. et al. Proteins, 1997, 29, 517–527.4. Carvahlo, A. L. et al. PNAS, 2003, 100, 13809–13814.
Mechanism Cellulosome self-assembly driven by non-specific but highly complementary cohesin/dockerin interactions
Featureso 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
o cooperative binding by carbohydrate binding modules (CBMs)o binding between dockerin and cohesin is species specifico cohesin is a 9-stranded β - sandwich with a jellyroll topologyo Scaffoldin-cellulase superstructure results in synergistic cellulolytic
activity not seen with free floating cellulases
Scaffoldin and thedockerin-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.