Event
Bioengineering Seminar Series: Amy J. Karlsson
Friday, September 30, 2016
9:00 a.m.
Pepco Room (1105), Jeong H. Kim Engineering Building
Silvina Matysiak
matysiak@umd.edu
Amy J. Karlsson
Assistant Professor
Department of Chemical & Biomolecular Engineering
University of Maryland
Engineered Proteins and Peptides as Versatile Biological Tools
Our lab uses both rational design and directed evolution to engineer proteins and peptides as molecular tools for studying protein-protein interactions and for designing better therapeutics. One thrust of our rational design work is developing improved approaches for assays involving antibody fragments and other proteins. We have developed a simple method to immobilize antibody fragments that utilizes the high-affinity interaction of streptavidin and biotin and does not require a separate purification step. Immobilized antibody fragments retain their ability to detect target antigen after at least 100 days of storage, allowing potential applications in diagnostics and screening of protein-protein interactions. A second thrust of our rational design work is engineering peptides for targeting the pathogen Candida albicans. We have engineered the antifungal peptide histatin-5 for reduced susceptibility to C. albicans secreted aspartic proteases without a loss of antifungal activity. We are also harnessing peptides as molecular vehicles for delivering cargo into the cytosol of C. albicans, while gaining information on the structural characteristics of the peptides that are important for cellular uptake. In addition to our rational design work, we are employing directed evolution to engineer antibody fragments that fold and function inside cells, with the goal of using the antibodies to block the function of intracellular proteins. Our screening approach harnesses the cytoplasmic folding quality control mechanisms of the Escherichia coli twin-arginine translocation pathway to engineer proteins able to fold in the cytosol, where the reducing environment typically prevents antibodies from properly folding and functioning. The protein engineering strategies we use and develop in our lab will enable new applications of proteins and peptides in studying biological phenomena and new approaches to therapeutic development.
