Journal Article

Robust proteome profiling of cysteine-reactive fragments using label-free chemoproteomics

Wilders, Harry, Biggs, George S., Vuorinen, Aini, Nightingale, Luke, Chen, Peiling, van der Zouwen, Antonie J., Boulton, Simon J., Bush, Jacob T., Cawood, Emma E., Pettinger, Jonathan, Powell, Andrew J., Rittinger, Katrin, Skehel, J. Mark, McCarthy, William J., Riziotis, Ioannis G., House, David

2025

Overview

Identifying pharmacological probes for human proteins represents a key opportunity to accelerate the discovery of new therapeutics. High-content screening approaches to expand the ligandable proteome offer the potential to expedite the discovery of novel chemical probes to study protein function. Screening libraries of reactive fragments by chemoproteomics offers a compelling approach to ligand discovery, however, optimising sample throughput, proteomic depth, and data reproducibility remains a key challenge. We report a versatile, label-free quantification proteomics platform for competitive profiling of cysteine-reactive fragments against the native proteome. This high-throughput platform combines SP4 plate-based sample preparation with rapid chromatographic gradients. Data-independent acquisition performed on a Bruker timsTOF Pro 2 consistently identified ~23,000 cysteine sites per run, with a total of ~32,000 cysteine sites profiled in HEK293T and Jurkat lysate. Crucially, this depth in cysteinome coverage is met with high data completeness, enabling robust identification of liganded proteins. In this study, 80 reactive fragments were screened in two cell lines identifying >400 ligand-protein interactions. Hits were validated through concentration-response experiments and the platform was utilised for hit expansion and live cell experiments. This label-free platform represents a significant step forward in high-throughput proteomics to evaluate ligandability of cysteines across the human proteome. This paper presents a label-free chemoproteomics platform using data-independent acquisition to profile covalent fragment binding across the human proteome. The platform offers high reproducibility and data completeness, identifying >400 protein-ligand interactions for probe development.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 631/154/1435/2163 / 631/1647/2067 / 631/92/475 / 82/58 / Cell lines / Completeness / Cysteine / Cysteine - metabolism / Fragments / HEK293 Cells / High-Throughput Screening Assays - methods / Humanities and Social Sciences / Humans / Jurkat Cells / Labels / Ligands / multidisciplinary / Probes / Protein interaction / Proteins / Proteome - metabolism / Proteomes / Proteomics / Proteomics - methods / Reproducibility / Reproducibility of Results / Robustness / Sample preparation / Science / Science (multidisciplinary) / Screening