Diamond Annual Review 2025-26

Fast fragment discovery with protein crystals Using the high-throughput I04-1 beamline, researchers have developed a faster way to turn weak early drug- discovery “fragments” into more promising chemical leads. Fragment-based drug discovery starts with very small molecules that bind weakly to a target protein. These fragments can be built up into stronger binders, but take repeated cycles of making, purifying and analysing each new compound. That process is slow and limits how much chemical space researchers can explore. The new method, called Binding-Site Purification of Actives, or B-SPA, avoids purifying every reaction product. Instead, researchers make many crude reaction mixtures and soak them directly into protein crystals. X-ray crystallography is then used to see whether any molecule in the mixture binds to the protein. MX is a core activity at Diamond with seven beamlines (I03, I04, I04-1, I23, I24, VMXi and VMXm) dedicated to the technique alongside the XFEL Hub, Membrane Protein Laboratory, Crystallisation Facility and XChem fragment screening. The beamlines cover a broad range of capabilities from high throughput, micro- and nano-focus beams, extremely long wavelengths, room temperature in situ collection from crystallisation plates and (time- resolved) serial synchrotron crystallography (SSX). One new future capability will be the exploitation of high energy electrons with the electron diffraction instrument HeXI currently in development following funding from the Wellcome Trust. Additionally, as part of the Diamond-II upgrade, XChem fragment screening will be transformed into a fully automated pipeline at the new K04 beamline, providing the capability to deliver larger campaigns while also investigating more challenging protein targets. Macromolecular crystallography (MX) exploits high flux X-rays to investigate the structure and function of biological macromolecules at atomistic resolution and up tomillisecond timescales. This provides deep insight into the details of biological activity key to the understanding of the processes of life. Macromolecular Crystallography Group The team explored chemical changes around a fragment that binds to the second bromodomain of PHIP, a protein linked to epigenetic regulation and cancer. They carried out 1,876 reactions, with 1,108 producing the intended product, and solved 22 protein–compound structures directly from crude mixtures. The approach acts like a structural filter, identifying useful binders even when they are minor components. It could reduce purification work, speed up hit-to-lead development and help drug-discovery teams make better decisions earlier. DOI: 10.1002/anie.202424373 Decoding how enzymes process healing fats Nitroalkene fatty acids are naturally occurring lipid signalling molecules. They help regulate inflammation and cellular stress responses by modifying key proteins involved in protective signalling pathways. Understanding how they are metabolised is crucial to both fundamental biology and drug development. Until recently, it was thought that their reaction with glutathione, a small molecule essential for cellular detoxification, happened spontaneously, without help from enzymes. Researchers learned that members of the human glutathione transferase (GST) enzyme family can catalyse this reaction with remarkable efficiency. Using ambient temperature macromolecular crystallography at the VMXi beamline, the team solved the crystal structure of one of these enzymes bound to the reaction product, providing unprecedented insight into the molecular details of this transformation. The findings show that detox enzymes may help control how long these anti-inflammatory fatty acids remain active in cells. This could improve understanding of lipid metabolism and support the design of future therapies based on these protective molecules. DOI: 10.1016/j.jbc.2025.108362 15 16 Annual review 2025/26 Macromolecular Crystallography Group