title: Stilbene vinyl sulfonamides as fluorogenic sensors of and traceless covalent kinetic stabilizers of transthyretin that prevent amyloidogenesis.
abstract: Small molecules that react selectively with a specific non-enzyme drug-target protein in a complex biological environment without displacement of a leaving group (tracelessly) are rare and highly desirable. Herein we describe the development of a family of fluorogenic stilbene-based vinyl amides and vinyl sulfonamides that covalently modify transthyretin (TTR) tracelessly. These small molecules bind selectively to TTR in complex biological environments and then undergo a rapid and chemoselective 1,4-Michael addition with the pKa-perturbed Lys-15 ε-amino group of TTR. Replacing the vinyl amide in 2 with the more reactive vinyl sulfonamide in 4 hastens the conjugation kinetics. X-ray cocrystallography verified the formation of the secondary amine bond mediating the conjugation in the case of 2 and 4 and confirmed the expected orientation of the stilbene within the TTR binding sites. Vinyl amide 2 and vinyl sulfonamide 4 potently inhibit TTR dissociation and amyloid fibril formation in vitro. The TTR binding selectivity, modification yield, and reaction chemoselectivity of vinyl sulfonamide 4 are good enough in human plasma to serve as a starting point for medicinal chemistry efforts. Moreover, vinyl sulfonamide 4 is fluorogenic: it exhibits minimal background fluorescence in complex biological environments, remains dark upon binding to TTR, and becomes fluorescent only upon reaction with TTR. The fluorogenicity of 4 was utilized to accurately quantify the native TTR concentration in Escherichia coli lysate using a fluorescence plate reader.
authors.affiliation: Department of Chemistry, ‡The Skaggs Institute for Chemical Biology, §Department of Integrative Structural and Computational Biology, and ∥Department of Molecular and Experimental Medicine, The Scripps Research Institute , La Jolla, California 92037, United States.
authors.forename: Eul Hyun
authors.initials: EH
authors.lastname: Suh
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Stephen
authors.initials: S
authors.lastname: Connelly
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Genereux
authors.forename: Ian A
authors.initials: IA
authors.lastname: Wilson
authors.forename: Jeffery W
authors.initials: JW
authors.lastname: Kelly
mesh_terms: D000577:Amides / Q000737:chemistry / Q000494:pharmacology; D000682:Amyloid / Q000037:antagonists & inhibitors* / Q000378:metabolism; D018360:Crystallography, X-Ray; D005456:Fluorescent Dyes / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D011228:Prealbumin / Q000378:metabolism*; D013267:Stilbenes / Q000737:chemistry / Q000494:pharmacology*; D013449:Sulfonamides / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000577:Amides; D000682:Amyloid; D005456:Fluorescent Dyes; D011228:Prealbumin; D013267:Stilbenes; D013449:Sulfonamides; C440389:vinyl sulfonamide