In a groundbreaking advance poised to revolutionize drug discovery and molecular biology, researchers at UCLA have developed a cutting-edge technology named SEE-CITE. This innovative approach enables scientists to map the precise binding sites of small molecules on proteins with unprecedented accuracy and consistency. By enhancing an already powerful experimental method known as photo-crosslinking, SEE-CITE offers a novel means to directly compare the binding affinities and specificities of different molecules, opening new avenues for understanding drug interactions and protein function.
At the core of SEE-CITE lies a clever chemical engineering strategy that overcomes one of photo-crosslinking’s long-standing limitations: inconsistent and messy chemical tags. Traditional photo-crosslinking involves attaching a reactive chemical group to a molecule, which, upon UV light activation, permanently binds to nearby proteins. While this method can reveal where a molecule interacts with a protein, the chemical “footprint” it leaves behind varies substantially between molecules, complicating direct comparisons. SEE-CITE introduces a detachable linker that leaves behind a uniform chemical signature upon crosslinking, enabling highly quantitative and reproducible measurements across different small molecules.
The implications of this uniform tagging system are profound. SEE-CITE effectively converts the qualitative nature of early photo-crosslinking techniques into a powerful quantitative platform. Researchers can now rank how strongly various compounds bind to particular protein sites, assess competitive binding among molecules, and identify previously unobserved off-target interactions. This level of detail is especially critical in drug discovery, where understanding both on-target efficacy and off-target effects can guide safer and more effective therapeutics.
To demonstrate the technology’s promise, the UCLA-led team focused on two FDA-approved kinase inhibitors: dasatinib and ascinimib. Kinases are a key class of enzymes implicated in many cancers, including leukemias, and are major targets for targeted therapies. The study revealed distinct binding patterns that confirmed prior knowledge but also uncovered novel interaction sites. Notably, ascinimib exhibited fewer unintended kinase interactions than dasatinib, which correlates with its improved clinical safety and tolerability profile. This insight underscores SEE-CITE’s potential to differentiate subtle differences in drug-target engagement that can affect patient outcomes.
Beyond validating and extending existing pharmacological data, SEE-CITE’s capabilities make it an indispensable tool for both fundamental biology and clinical drug development. Understanding the exact molecular choreography of small molecules as they engage proteins can illuminate how cellular pathways are modulated in health and disease states. Furthermore, by mapping off-target interactions, scientists can proactively identify and mitigate side effects, a critical step for bringing new drugs safely to market.
The innovation did not stop with the chemistry alone. To handle the complex and rich data generated by SEE-CITE experiments, the researchers enhanced existing bioinformatics software. This upgrade allows for rigorous analysis, efficient data integration, and clearer visualization of binding site landscapes—a crucial element given the vast complexity of proteomic datasets. The seamless interface between chemical innovation and computational analysis represents a holistic approach to tackling molecular interaction challenges.
Historically, drug discovery efforts have been impeded by incomplete knowledge of where and how candidate drugs bind their targets. Techniques like X-ray crystallography and cryo-electron microscopy provide exquisite structural snapshots but are laborious and low throughput. In contrast, photo-crosslinking paired with mass spectrometry offers the ability to probe interactions directly in biological contexts and on a proteome-wide scale. SEE-CITE elevates this method by ensuring that the tagging chemistry is not a bottleneck, but a precise and versatile tool.
The ramifications for diseases beyond cancer are equally exciting. Small molecules modulate a broad swath of biological systems, influencing cholesterol metabolism, liver function, immune responses, and metabolic disorders. SEE-CITE’s capacity to pinpoint binding sites in these diverse contexts promises to accelerate the discovery of novel therapeutics and deepen the understanding of molecular mechanisms underlying complex diseases.
This collaborative research endeavor integrated expertise from UCLA’s renowned departments of biological chemistry and chemical biology, the University of Michigan, leading European institutes, and the global biopharmaceutical firm Daiichi Sankyo. Such multi-institutional cooperation highlights the emerging importance of interdisciplinary approaches in pushing the envelope of bioscience innovation.
Crucially, UCLA has sought to protect this technology through an active patent application, ensuring control over its development and broad accessibility to academic and industry researchers alike. As one of the corresponding investigators, Associate Professor Keriann Backus leads this mission to create tools that comprehensively profile the molecular interactions shaping biology and medicine.
Looking ahead, SEE-CITE may become a standard platform in the chemoproteomic toolkit. Its ability to generate detailed, quantitative binding-site maps fosters a new paradigm where drug candidates can be evaluated holistically, not just for binding affinity but for selectivity and safety profiles at an early stage. As such, the technology aligns perfectly with the growing emphasis on precision medicine and personalized therapeutics.
From elucidating subtle nuances of kinase inhibitors to exploring new frontiers in metabolite-protein interactions, SEE-CITE embodies how chemical biology innovations can propel both scientific understanding and therapeutic advancements. By bridging the gap between molecular chemistry and proteomic biology, UCLA researchers have provided the scientific community a powerful lens to decode the intricate dance of molecules within the living cell.
In essence, the development of SEE-CITE reflects a watershed moment in chemical proteomics—a fusion of chemistry, biology, and computation that elevates the resolution at which we observe and manipulate the fundamental interactions governing life and disease. Its continued application promises to yield discoveries that resonate from the laboratory bench all the way to clinical practice and patient care.
Subject of Research: Small-molecule binding-site discovery, protein–drug interaction mapping, chemoproteomics.
Article Title: Small-molecule binding-site discovery using silyl ether-enabled chemoproteomics
News Publication Date: 27-Apr-2026
Web References:
https://www.nature.com/articles/s41557-026-02127-4
Image Credits: CNSI at UCLA
Keywords
Drug discovery, chemoproteomics, photo-crosslinking, protein binding sites, kinase inhibitors, molecular pharmacology, chemical biology, precision medicine, proteomics, drug safety, small molecules, biochemical methods
Tags: chemical linker innovationdrug discovery technologydrug interaction profilingmolecular probe enhancementphoto-crosslinking limitationsprotein function elucidationprotein-ligand interaction analysisquantitative molecular mappingSEE-CITE photo-crosslinkingsmall molecule protein bindingUCLA molecular biology researchuniform chemical tagging
