The world of scientific research is a fascinating one, and the latest advancements in protein crystallography are no exception. In this article, I'll delve into the intricacies of electron diffraction of intracellular protein crystals and the innovative workflow that has been developed to access these crystals. This cutting-edge technique, known as IncelluloED, is revolutionizing the field by bypassing time-consuming purification steps and broadening the range of applicable target proteins. But what makes this approach truly remarkable is the challenge it addresses: reliably localizing and targeting rare crystals within crowded cellular environments. This is no easy feat, especially when precise three-dimensional positioning is crucial to avoid missing the target during milling. The key to success lies in a combination of cryo-fluorescence-based localization and targeted cryo-FIB milling using the Tescan AMBER system. This system enables precise targeting and preparation of lamellae from selected regions of interest, ensuring that intracellular crystals are accessible for electron diffraction analysis. The challenge statement highlights the difficulty of identifying rare crystals within thick cellular volumes, which are beyond the practical penetration depth of electrons in TEM. This is where fluorescence-guided approaches come into play, providing a reliable localization and correlation with cryo-FIB, ensuring accurate transfer of positional information and improving targeting reliability. The result? A significant increase in the success rate of accessing intracellular crystals suitable for electron diffraction analysis. This breakthrough has far-reaching implications for the field of structural biology, enabling the study of protein structures that were previously inaccessible. The workflow presented here is a testament to the power of innovation and collaboration, with contributions from researchers at various institutions. The full publication, including detailed descriptions of the workflow and representative results, is available for download, offering a wealth of information for those interested in this groundbreaking research. In conclusion, the IncelluloED pipeline and the fluorescence-guided, site-specific cryo-FIB approach represent a significant advancement in the field of protein crystallography. By addressing the challenges of localizing and targeting rare crystals, this technique opens up new possibilities for understanding protein structures and their functions. As we continue to push the boundaries of scientific discovery, it's exciting to see how these advancements will shape the future of research.
