With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Mark Peczuh at the University of Connecticut to transform a beta-glucosyl hydrolase from Streptomyces that normally cleaves the beta-1,4-linkage between glucose residues in cellobiose into a glycosynthase that attaches a seven-membered ring septanose onto a glucose residue. Carbohydrates are biological polymers essential to numerous functions of plant and animal life. They are built up through the sequential addition of monomers by one type of enzyme or broken down by another, completely different type of enzyme; natural carbohydrates are composed primarily of monomers with a six-atom ring. This project will develop a new type of enzyme for attaching unique, seven-atom ring monomers to carbohydrates. Moreover, the new enzyme will be derived from a degradative enzyme that has been engineered to work in reverse. That is, through genetic engineering, a degradative enzyme will be converted to a synthetic enzyme. Efforts to achieve this goal will be through an international collaborative team of graduate student chemists and bioengineers. The new enzyme plus the method used to design and create it will be a training ground for a number of interdisciplinary techniques and ideas. The researchers will directly engage non-scientists to amplify the impact of the results and their enthusiasm for the research process.
Glycosynthases are mutant enzymes, derived from natural glycosyl hydrolases that form rather than cleave glycosidic linkages. The project links the expertise in septanose carbohydrate synthesis and characterization in the Peczuh research group with the group of Dr. Antoni Planas at IQS in the University of Ramon Lllull in Barcelona Spain. The development process will provide information about septanose conformations, protein-septanose interactions and enzyme dynamics. Only a few glycosynthases that couple unnatural sugars to another molecule have been successfully developed which makes this investigation particularly challenging. Individual aims within the proposal represent a step-wise approach toward the overall goal of a functional glycosynthase; the development strategy is to optimize activity for the hydrolysis reaction for the new substrate and then convert the glycosidase into a glycosynthase.
