Structure‐Based Design of Fluorogenic Substrates Selective for Human Proteasome Subunits

ChemBioChem, vol. 21, pp. 3220–3224

Abstract

Proteasomes are established therapeutic targets for hematological cancers and promising targets for autoimmune diseases. In the past, we have designed and synthesized mechanism-based proteasome inhibitors that are selective for the individual catalytic activities of human constitutive proteasomes and immunoproteasomes: β1c, β1i, β2c, β2i, β5c and β5i. We show here that by taking the oligopeptide recognition element and substituting the electrophile for a fluorogenic leaving group, fluorogenic substrates are obtained that report on the proteasome catalytic activity also targeted by the parent inhibitor. Though not generally applicable (β5c and β2i substrates showing low activity), effective fluorogenic substrates reporting on the individual activity of β1c, β1i, β2c and β5i subunits in Raji (human B cell) lysates and purified 20S proteasome were identified in this manner. Our work thus adds to the expanding proteasome research toolbox through the identification of new and/or more effective subunit-selective fluorogenic substrates.

Authors 5

1. Elmer Maurits Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands

   Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands

2. Christian G. Degeling Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands

   Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands

3. Alexei F. Kisselev

   Auburn University

   Affiliation as printed

   Department of Drug Discovery and Development Harrison School of Pharmacy Auburn University Auburn AL 36849 USA

   Department of Drug Discovery and Development Harrison School of Pharmacy Auburn University Auburn AL 36849 USA

4. Bogdan I. Florea corresponding Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands

   Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands

5. Herman S. Overkleeft corresponding Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands

   Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands