(584aw) A Conformation-Switching, Intrinsically Disordered Protein Probe for Detection of Amyloid Oligomers

Amyloid aggregation of intrinsically disordered proteins (IDPs), such as α synuclein (αS) in Parkinson's disease (PD), is a molecular process producing structurally similar yet different oligomeric and fibrillar protein aggregates. In this study, motivated by Nature's use of IDPs as conformation-switching biosensors, we engineered an αS variant together with conformation-sensitive fluorescence to create a novel molecular probe platform for rapid, specific and quantitative detection of αS oligomers, which are the major toxic aggregate forms in PD. Our results suggest that our molecular probe was bound to β sheet-structured αS oligomers, and this binding event was functionally linked to fluorescence signaling. A linkage between binding and signaling could be tuned by binding-induced conformational changes of our molecular probe, enabling selective detection of αS oligomers over unfolded αS monomers, structurally similar αS fibrils and other amyloid oligomers. Our strategy to engineer the structural flexibility of IDP represents a new paradigm for designing rapid-responsive, conformation-switching molecular probes for detection of specific protein forms mediated by not only binding to analytes but also its linkage to signaling.