|French, Alfred - Al|
Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2005
Publication Date: 8/28/2005
Citation: French, A.D., Johnson, G.P., Lauterbach, B., Reilly, P. Linkage distortion energies for carbohydrates in complexes with crystalline proteins: Basic research for future innovations of industial enzymes. 2005. Abstract No. CARB51. Interpretive Summary:
Technical Abstract: Original work (Phillips, D. C. Sci Amer 1966, 215, 78-90) on carbohydrate enzymology showed that the monosaccharide residues can be distorted as part of the bond cleavage reaction. This distortion was obvious because the galactose ring deviated from the normal chair conformation. The inter-monomer torsion angles are another potential location of distortion. If these linkage torsion angles denoted by Phi and Psi are sometimes distorted by enzymatic reactions, it could be that engineering the enzyme to create greater distortion might make it a more efficient hydrolase. To learn whether linkage distortion occurs during enzyme action, it is necessary to survey the existing geometries in carbohydrate-protein complexes that have been determined by crystallography. The most unusual conformations may be distorted as part of the catalytic action if it can be shown that the carbohydrate molecules are at the active site in an enzyme. Another type of information is whether the values of Phi and Psi correspond to high calculated potential energies on an energy surface. We have continued to develop energy surfaces in the hopes of obtaining accurate values for the energies of linkage distortion. For the present work we have utilized pure ab initio quantum mechanics calculations as well as QM/MM studies to obtain energies and have examined the details of hundreds of protein carbohydrate interactions. The most interesting interactions are with lactose based carbohydrates.