(3p) Engineering Responsive Proteins for Synthetic Biology

Chemical engineers have made great advances in heterologous expression of proteins and synthetic pathways used to create complex biomolecules and reprogram cell behavior.  However, understanding and engineering dynamic control of these proteins and pathways has been less explored.  Nature provides many examples in which environmental signals (temperature, pH, and shear force) or specific stimuli (metal ions, small molecules, and other proteins) are used to control protein conformation and spatial organization, resulting in regulation of protein and pathway functions.  New tools for conformational and spatial control of proteins and pathways will have broad impact on synthetic biology, leading to modular components that allow microbes to sense and respond to environmental changes, construction of pathways that integrate multiple signals, more selective therapeutic targeting by spatial regulation of protein function, and spatial control of enzymatic reactions to increase product formation. My research group will focus on using protein engineering and directed evolution to design responsive behavior into proteins and pathways in order to address critical problems in bioenergy, heath, and the environment. We will apply techniques and concepts from my doctoral and postdoctoral research when possible and forge new concepts and technology towards engineering responsive proteins.

Here I present my work towards engineering stimulus responsive proteins and peptides as well as developing tools for examining their mechanisms of conformational change.  My doctoral research (with Scott Banta, Columbia University – Chemical Engineering) examined stimulus responsive peptides, including engineered beta roll scaffolds that fold and unfold by binding and releasing calcium, and utilized single-chain antibodies as conformational change sensors.  My postdoctoral research (with Timothy Springer, Harvard Medical School) focuses on using directed evolution in combination with a novel selection method to engineer mutants of von Willebrand Factor (VWF) binding to platelet glycoprotein Ib (GPIb) stabilized in their alternative force-activated conformation.  VWF initiates primary hemostasis at the site of vascular injury by binding to platelets through GPIb only in the presence of elevated shear stress.  Consequently, this interaction is spatially controlled to where clotting is needed.