title: On the mechanism of nonspecific inhibitors of protein aggregation: dissecting the interactions of alpha-synuclein with Congo red and lacmoid.
abstract: Increasing evidence links the misfolding and aberrant self-assembly of proteins with the molecular events that underlie a range of neurodegenerative diseases, yet the mechanistical details of these processes are still poorly understood. The fact that many of these proteins are intrinsically unstructured makes it particularly challenging to develop strategies for discovering small molecule inhibitors of their aggregation. We present here a broad biophysical approach that enables us to characterize the mechanisms of interaction between alpha-synuclein, a protein whose aggregation is closely connected with Parkinson's disease, and two small molecules, Congo red and Lacmoid, which inhibit its fibrillization. Both compounds are found to interact with the N-terminal and central regions of the monomeric protein although with different binding mechanisms and affinities. The differences can be attributed to the chemical nature of the compounds as well as their abilities to self-associate. We further show that alpha-synuclein binding and aggregation inhibition are mediated by small oligomeric species of the compounds that interact with distinct regions of the monomeric protein. These findings provide potential explanations of the nonspecific antiamyloid effect observed for these compounds as well as important mechanistical information for future drug discovery efforts targeting the misfolding and aggregation of intrinsically unstructured proteins.
authors: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
authors: Christofer
authors: C
authors: Lendel
authors: Carlos W
authors: CW
authors: Bertoncini
authors: Nunilo
authors: N
authors: Cremades
authors: Christopher A
authors: CA
authors: Waudby
authors: Michele
authors: M
authors: Vendruscolo
authors: Christopher M
authors: CM
authors: Dobson
authors: Dale
authors: D
authors: Schenk
authors: John
authors: J
authors: Christodoulou
authors: Gergely
authors: G
authors: Toth
mesh_terms: D003224:Congo Red / Q000378:metabolism*; D006801:Humans; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D015394:Molecular Structure; D019636:Neurodegenerative Diseases / Q000378:metabolism*; D010300:Parkinson Disease / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D015398:Signal Transduction; D054852:Small Molecule Libraries / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D051844:alpha-Synuclein / Q000737:chemistry* / Q000378:metabolism
chemical_list: D054852:Small Molecule Libraries; D051844:alpha-Synuclein; D003224:Congo Red