Chemical Proteomics for Expanding the Druggability of Human Disease

Measurement and utilization of the proteomic reactivity by mass spectrometry

Chemical proteomics, which involves studying the covalent modifications of proteins by small molecules, has significantly contributed to our understanding of protein function and has become an essential tool in drug discovery. Mass spectrometry (MS) is the primary method for identifying and quantifying protein-small molecule adducts. In this review, we discuss various methods for measuring proteomic reactivity using MS and covalent proteomics probes that engage through reactivity-driven and proximity-driven mechanisms. We highlight the applications of these methods and probes in live-cell measurements, drug target identification and validation, and characterizing protein-small molecule interactions. We conclude the review with current developments and future opportunities in the field, providing our perspectives on analytical considerations for MS-based analysis of the proteomic reactivity landscape.

Mapping the Evolution of Activity-Based Protein Profiling: A Bibliometric Review

Activity-based protein profiling (ABPP) is a chemoproteomic approach that employs small-molecule probes to directly evaluate protein functionality within complex proteomes. This technology has proven to be a potent strategy for mapping ligandable sites in organisms and has significantly impacted drug discovery processes by enabling the development of highly selective small-molecule inhibitors and the identification of new therapeutic molecular targets. Despite being nearly a quarter of a century old as a chemoproteomic tool, ABPP has yet to undergo a bibliometric analysis. In order to gauge its scholarly impact and evolution, a bibliometric analysis was performed, comparing all 1919 reported articles with the articles published in the last five years. Through a comprehensive data analysis, including a 5-step workflow, the most influential articles were identified, and their bibliometric parameters were determined. The 1919 analyzed articles span from 1999 to 2022, providing a comprehensive overview of the historical and current state of ABPP research. This analysis presents, for the first time, the characteristics of the most influential ABPP articles, offering valuable insight into the research conducted in this field and its potential future directions. The findings underscore the crucial role of ABPP in drug discovery and novel therapeutic target identification, as well as the need for continued advancements in the development of novel chemical probes and proteomic technologies to further expand the utility of ABPP.

Chemical proteomic identification of functional cysteines with atypical electrophile reactivities

Cysteine-directed covalent ligands have emerged as a versatile category of chemical probes and drugs that leverage thiol nucleophilicity to form permanent adducts with proteins of interest. Understanding the scope of cysteines that can be targeted by covalent ligands, as well as the types of electrophiles that engage these residues, represent important challenges for fully realizing the potential of cysteine-directed chemical probe discovery. Although chemical proteomic strategies have begun to address these important questions, only a limited number of electrophilic chemotypes have been explored to date. Here, we describe a diverse set of candidate electrophiles appended to a common core 6-methoxy-1,2,3,4-tetrahydroquinoline fragment and evaluate their global cysteine reactivity profiles in human cancer cell proteomes. This work uncovered atypical reactivity patterns for a discrete set of cysteines, including residues involved in enzymatic catalysis and located in proximity to protein-protein interactions. These findings thus point to potentially preferred electrophilic groups for site-selectively targeting functional cysteines in the human proteome.