DOE Bioenergy Research Centers

Title :

The Cellulosome

Description :

Nature has devised two types of enzyme-based strategies for breaking down plant cell walls. One strategy observed in oxygen-rich environments involves fungi and bacteria that secrete individual enzymes with complementary cell wall– degrading functions. A second strategy occurring in oxygen-free environments is exhibited by bacteria that produce cellulosomes—large complexes that degrade the cell wall by assembling several different enzymes into a single protein structure. Cellulosomes protrude from bacterial surfaces, latch onto plant cell walls, and tear carbohydrates into simple sugars. Clostridium thermocellum, a model bacterium for studying cellulosomes, can produce more than 25 different cell wall–degrading enzymes that it can “plug and play” into its large protein scaffold (see figure, The Cellulosome). By sensing the surrounding environment, Clostridium thermocellum can modify the functionality of its cellulosomes on demand by assembling different combinations of enzymes to attack various compounds in the plant cell wall. The LEGO-like arrangement of enzymes in cellulosomes offers a unique opportunity to engineer “designer” multienzyme complexes targeted to specific biomass types or for different stages of biomass deconstruction.

Citation :

Bioenergy Research Centers: An Overview of the Science, U.S. Department of Energy, February 2008. DOE/SC-0104.

Credit or Source :

Genome Management Information System, Oak Ridge National Laboratory

Medium Res :

Medium-Resolution Image

Hi Res :

High-Resolution Image

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