Paradigm for Improving Catalytic Ability of Industrial Enzymes: Linkage Distortions of Carbohydrates in Complexes with Crystalline Proteins

Authors: French, Alfred - Al; Johnson, Glenn

Submitted to: American Chemical Society Symposium Series
Publication Type: Book / Chapter
Publication Acceptance Date: 6/7/2006
Publication Date: 8/7/2007
Citation: French, A.D., Johnson, G.P. 2007. Paradigm for Improving Catalytic Ability of Industrial Enzymes: Linkage Distortions of Carbohydrates in Complexes with Crystalline Proteins. American Chemical Society Symposium Series. 972:207-219.

Interpretive Summary: Improvements of proteins that convert agricultural products into particular food ingredients or other useful items such as fuel or chemical feedstocks could lower the cost of the conversions. However, such improvements depend on the knowledge of the mode of action of the protein on the agricultural product. This work explores the idea that a twisting of the agricultural molecules such as cellulose is often a part of the mechanism of action of a catalytic protein. This work is of primary interest to scientists engaged in the modification of proteins for such work, and to those who study the structures of enzymes that act on carbohydrate materials.

Technical Abstract: Future innovations in applications of industrial enzymes to carbohydrates will require improved knowledge of the mode of action. This chapter explores whether one aspect of enzymatic hydrolysis of saccharides is a twisting distortion of the bonds between adjacent monosaccharides in larger carbohydrate substrates. If such distortion is important, then new enzymes could be engineered that would, for example, increase the distortion for faster reaction. One way to learn if linkage distortion occurs is to survey existing geometries in crystalline carbohydrate-protein complexes. Unusual conformations may be distorted as part of the catalytic action if they are at the active site in an enzyme. A related question is whether twisting of the linkage bonds increases the molecular potential energy. For the present work we have tracked the degree of twisting in hundreds of protein–carbohydrate structures and we have used improved computer modeling studies of cellobiose to obtain energies. The largest apparent distortions were in similar, molecules based on lactose.