1. A Photocrosslinking Probe to Capture the Substrates of Caseinolytic Protease P.
- Author
-
Gronauer TF, Eck LK, Ludwig C, and Sieber SA
- Subjects
- Substrate Specificity, Cross-Linking Reagents chemistry, Photochemical Processes, Molecular Probes chemistry, Molecular Probes metabolism, Endopeptidase Clp metabolism, Endopeptidase Clp chemistry, Staphylococcus aureus enzymology
- Abstract
Protein homeostasis in bacteria is regulated by proteases such as the tetradecameric caseinolytic protease P (ClpP). Although substrates of ClpP have been successfully deciphered in genetically engineered cells, methods which directly trap processed proteins within native cells remain elusive. Here, we introduce an in situ trapping strategy which utilizes trifunctional probes that bind to the active site serine of ClpP and capture adjacent substrates with an attached photocrosslinking moiety. After enrichment using an alkyne handle, substrate deconvolution by mass spectrometry (MS) is performed. We show that our two traps bind substoichiometrically to ClpP, retain protease activity, exhibit unprecedented selectivity for Staphylococcus aureus ClpP in living cells and capture numerous known and novel substrates. The exemplary validation of trapped hits using a targeted proteomics approach confirmed the fidelity of this technology. In conclusion, we provide a novel chemical platform suited for the discovery of serine protease substrates beyond genetic engineering., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)
- Published
- 2024
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