|CBP21, a non-catalytic protein, promotes the breakdown of chitin.|
Researchers from Norway and the UK have discovered a new protein that is essential for the degradation of the biopolymer chitin. This new molecule could eventually lead to the discovery of similar molecules that could be used in the production of cellulose-based biofuels.
A paper describing the research is published in the August 5 issue of the Journal of Biological Chemistry.
Chitin is an insoluble molecule consisting of tightly packed chains of polymerized sugars that is a major structural component for crustaceans, mollusks, algae, insects, fungi and yeasts .
More than one billion tons of chitin are produced by insects, fungi, and marine organisms every year—yet the absence of accumulation in most ecosystems indicates that chitin is successfully degraded.
Enzymes called chitinases are responsible for breaking down chitin, but the mechanism for breaking the bonds between the sugar units has been unclear until now.
The research team investigated chitin degradation by the soil bacterium Serratia marcescens, and discovered that in addition to producing chitinases, the bacterium also produces a protein called CBP21 (Chitin-Binding Protein) which binds to and disrupts the chitin polymer making it more accessible to degradation by chitinases.
They found that adding CBP21 dramatically speeds up the degradation of chitin by chitinases.
One might say that our discovery may lead to discovery of proteins with similar functions in cellulose processing. This may be of major important for the cellulose field and production of biofuel.—Dr. Vincent G. H. Eijsink, Norwegian University of Life Sciences
The Non-catalytic Chitin-binding Protein CBP21 from Serratia marcescens Is Essential for Chitin Degradation, Vaaje-Kolstad et al. J. Biol. Chem. 2005; 280: 28492-28497