title: Tunable Probes with Direct Fluorescence Signals for the Constitutive and Immunoproteasome.
abstract: Electrophiles are commonly used for the inhibition of proteases. Notably, inhibitors of the proteasome, a central determinant of cellular survival and a target of several FDA-approved drugs, are mainly characterized by the reactivity of their electrophilic head groups. We aimed to tune the inhibitory strength of peptidic sulfonate esters by varying the leaving groups. Indeed, proteasome inhibition correlated well with the pKaof the leaving group. The use of fluorophores as leaving groups enabled us to design probes that release a stoichiometric fluorescence signal upon reaction, thereby directly linking proteasome inactivation to the readout. This principle could be applicable to other sulfonyl fluoride based inhibitors and allows the design of sensitive probes for enzymatic studies.
authors.affiliation: Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany. christian.dubiella@mytum.de.
authors.forename: Christian
authors.identifier: 0000-0001-5801-2053
authors.initials: C
authors.lastname: Dubiella
authors.affiliation: Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.
authors.forename: Haissi
authors.identifier: 0000-0003-3358-8958
authors.initials: H
authors.lastname: Cui
authors.affiliation: Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany. michael.groll@tum.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Groll
mesh_terms: D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D015394:Molecular Structure; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000378:metabolism*; D061988:Proteasome Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D013441:Sulfinic Acids / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D005456:Fluorescent Dyes; D061988:Proteasome Inhibitors; D013441:Sulfinic Acids; C048899:sulfuryl fluoride; D046988:Proteasome Endopeptidase Complex
keywords: fluorescent probes; inhibitors; probe design; proteasome; structure-activity relationships