Chemically Induced Dimerization of Nanobodies for the Development of Versatile Biosensors
Chemically induced dimerization (CID), in which two proteins dimerize only in the presence of a small molecule, has been widely used to control cell signaling, regulatory, and metabolic pathways, and used as logic gates for biological computation in living mammalian cells. However, few naturally occuring CID systems and their derivatives are currently available. Creating a CID system with desired affinity and specificity for any given small molecule remains an unsolved problem for computational design and other protein engineering approaches. To address this challenge, we have used a novel strategy to select CID binders from a vastly diverse combinatorial nanobody library. We have created new CID systems that can sense cholecalciferol and artemisinin. We are validating CID biosensors by a yeast three-hybrid system and built structural models to understand the small molecule-induced dimerization. Our work is a proof-of-concept that can be generalized to create CID systems for many applications.