Helical Reconstruction (BETA)

CryoSPARC provides several specialized jobs to aid with processing of helical assemblies. While many single particle analysis (SPA) methods carry over quite well to helical assemblies, particle picking and refinement have been modified to better take advantage of the symmetry present in the dataset, ultimately leading to higher quality reconstructions. This page summarizes the new job types, and links to various other educational pages on the topic of helical reconstruction.

The Filament Tracer (BETA) provides a new template-based particle picking tool for identification of individual filaments, which can be useful for many datasets. Helical Refinement (BETA) allows for the direct reconstruction and high-resolution refinement of helical assemblies, and for the simultaneous enforcement and refinement of helical symmetry parameters. The Symmetry search utility (BETA) is a tool that can take a reconstructed volume and search for locally optimal symmetry parameters in a given search range.

Prior to the use of any helical reconstruction jobs, the page detailing helical symmetry in cryoSPARC should be read, as it details important information about:

• how helical symmetry is parameterized in cryoSPARC,

• possible workflows for helical reconstruction, and

• limitations in the case of unknown helical symmetry

As well, for an overview of an example workflow involving all of the new jobs introduced, it is highly recommended to view the EMPIAR-10031 case study. This case study outlines an example end-to-end workflow for helical reconstruction, that may be useful for reference.