Antibody-Based Affinity Cryo-Electron Microscopy at 2.6 Å Resolution

Abstract The affinity cryo-electron microscopy (cryo-EM) approach has been explored in recent years to simplify and improve the sample preparation for cryo-EM. Despite the demonstrated successes for low-concentration and unpurified specimens, the lack of near-atomic structures using this approach has led to a common perception of affinity cryo-EM as a niche technique incapable of reaching high resolutions. Here, we report a ~2.6 Å structure solved using the antibody-based affinity grid approach with a Tulane virus sample of low concentration. This is the first near-atomic structure solved using the affinity cryo-EM approach. Quantitative analyses of the structure indicate data and reconstruction quality comparable to conventional grid preparation method using samples at high concentration. With the shifting of bottlenecks of cryo-EM structural studies to sample grid preparation, our demonstration of the sub-3 Å capability of affinity cryo-EM approach indicates its potential in revolutionizing cryo-EM sample preparation for a broader spectrum of specimens.