Development of Methods for Cryo-EM Helical Reconstruction

Many biological macromolecules exist as helical assembly complexes. Atomic-level determination of their structures allows scientists to understand their biological functions and discover new drug targets. Cryo-electron microscopy (cryo-EM) has emerged as a powerful technique for structural studies of helical assembly complexes. However, the helical reconstruction of cryo-EM images typically requires prior determination of three critical factors: heterogeneity, helical parameters, and an ab initio model. The main scope of this dissertation is to develop a comprehensive pipeline to systematically address these three factors. This pipeline has been successfully applied to practical research problems, leading to the reconstruction of numerous high-resolution structures of helical assembly complexes. Additionally, we have developed another pipeline designed to validate and curate helical parameters deposited in the Electron Microscopy Data Bank (EMDB), identifying and correcting numerous errors. Through the tools and methodologies developed in this dissertation, we aim to significantly benefit the cryo-EM community, particularly researchers focused on structure determination of helical assembly complexes.