title: Engineering a signal transduction mechanism for protein-based biosensors.
abstract: Hybridization-induced conformational changes have been successfully used in biosensors for the transduction of DNA-binding events into readily observable optical or electronic signals. Similar signal transduction has not, however, proven of equal utility in protein-based biosensors. The discrepancy arises because, unlike ssDNA, most proteins do not undergo significant conformational changes upon ligand binding. Here, we describe a solution to this problem. We show that an arbitrarily selected, normally well folded protein can be rationally engineered such that it undergoes ligand-induced folding. The engineered protein responds rapidly (milliseconds) and selectively to its target, and it couples recognition with the largest possible conformational change: folding. These traits suggest that ligand-induced folding could serve as an ideal signal-transduction mechanism. Consistent with this claim, we demonstrate a label-free optical biosensor based on the effect that is sufficiently selective to detect its target even in complex, contaminant-ridden samples such as blood serum.
authors.affiliation: Interdepartmental Program in Biomolecular Science and Engineering, Department of Chemistry and Biochemistry, University of California-Santa Barbara, Santa Barbara, CA 93106, USA.
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Kohn
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Plaxco
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008024:Ligands; D016296:Mutagenesis; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D015202:Protein Engineering; D017510:Protein Folding; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction; D018909:src Homology Domains; D019061:src-Family Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D008024:Ligands; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn; D019061:src-Family Kinases