This research seeks to study the self-assembly process of cellulosomes, a group of natural protein complexes secreted by microorganisms for the highly efficient degradation of plant cell walls into fermentable sugars. A cellulosome consists of a core scaffoldin protein of structural function and several hydrolytic proteins of catalytic function. Assembly of the cellulosome occurs via interactions between cohesin domains of the scaffoldin protein and matching dockerin domains of catalytic modules. Due to the non-discriminatory nature of cohesin-dockerin recognition in a single microorganism, the assembled cellulosomes have diverse structural and molecular composition. The proposed research seeks to achieve regio- and stoichiometric controlled assembly of designer cellulosomes through engineering orthogonal cohesin-dockerin protein pairs with minimal crosstalking recognition. The engineered cohesin domains with altered specificity will be assembled at pre-arranged positions to form recombinant scaffoldin protein, which enables templated attachment of catalytic modules through matching dockerin domains to form designer cellulosomes. Their structure-activity relationships will be investigated.
The proposed research is expected to lead to synthetic cellulosomes that can outperform their natural counterparts in the process of plant cellulosic material degradation. It will contribute to the generation of biomass-derived feedstocks for biofuel and bioenergy production, which has potential to resolve many long-term economic and environmental concerns. Furthermore, a deeper understanding of the speed and precision of cellulosome self-assembly could lead to new strategies for the synthesis of self-assembled protein complexes with broad impact on the fields of biocatalysis, metabolic engineering, synthetic biology, and nanosciences. The proposed research represents an outstanding training opportunity for students at all levels of development. Students will be exposed in depth to a large array of research problems in chemistry and biology at the University of Nebraska. Some specific outreach activities include development of a summer research program for undergraduate students from four-year colleges and of chemistry lab kits for high school students. These activities will attract college and high school students, including specifically women and underrepresented students, to pursue studies and academic careers in STEM areas.
This project is jointly funded by the Biotechnology, Biochemical and Biomass Engineering Program of the Chemical, Bioengineering, Environmental, and Transport Systems Division, by the Systems and Synthetic Biology Program of the Division of Molecular and Cellular Biology, and by the Office of the Experimental Program to Stimulate Competitive Research (EPSCoR).
