Advances in Crystallography and Cryo-Electron Microscopy for the Study of Membrane Proteins.

The field of structural biology has undergone a remarkable transformation over the past decade, fueled by cutting-edge advancements in X-ray crystallography and cryo-electron microscopy (cryo-EM). Central to both approaches is the critical step of sample preparation, which includes heterologous expression of membrane proteins in host systems and extraction from the membrane environment using suitable membrane mimetics. In crystallography, enhanced techniques, such as lipidic cubic phase (LCP) crystallization and serial femtosecond crystallography (SFX), have pushed the boundaries of structure determination to microcrystals and conformationally labile targets. In cryo-EM, technical advancements across many levels have fueled the "resolution revolution," enabling cryo-EM to reach near-atomic resolution and driving single-particle analysis of increasingly small, dynamic, and heterogeneous macromolecular assemblies. Emerging modalities further extend our capability to tackle previously inaccessible questions. Cryo-electron tomography (cryo-ET) is extracting structural insights from native cellular environments, and micro-electron diffraction (MicroED) has opened new frontiers for nanoscale structural studies from submicron crystals at unprecedented resolution. Collectively, these advances have improved our ability to study the structure of challenging targets, with profound implications for structure-based drug discovery, and an evolving paradigm shift toward dynamic visualization of biomolecular processes, signaling the dawn of a new era in structural biology.