# High-Resolution CryoEM Reconstruction of Large Complexes

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 2023 · $85,328

## Abstract

PROJECT SUMMARY
Overall, this project aims to develop methods to efficiently determine, at atomic-resolution, three-dimensional
(3D) structures of large, native, symmetry-mismatched, locally dis-ordered or polymorphic biological complexes
through cryo electron microscopy (cryoEM). The past funding cycle of this project (2014-2019) has witnessed a
drastic transformation of the field of structural biology, popularly referred as “the cryoEM revolution”. Today,
single-particle cryoEM has arguably become the default choice for structural biology. The funding from this
project has enabled the PI’s group to contribute to this transformation in multiple fronts: we have developed
novel imaging and processing methods and validated these methods by determining in situ structures of
important—and sometimes fundamental—biological processes in large icosahedral and helical complexes, as
well as atomic models of purified protein-nucleic acid complexes and membrane proteins that have been
resistant to previous x-ray crystallography and NMR efforts. We hypothesize that combining electron counting
(i.e., quantum) capabilities with cryoEM can advance the field by determining atomic models of native cellular
complexes, viral genome packaging and transcription in situ and transiently stable catalytic intermediates.
 In the last funding period we aimed to, and succeeded in, derive atomic models using our cryoEM
method alone for larger complexes, particularly those in icosahedral and helical viruses. Now, this renewal
application aims to develop an integrative proteome cryoEM method for atomic structures of cellular
complexes in their native, unpurified, and functional states. We will also use viruses as tools to address
fundamental questions concerning genome packaging, compaction, supercoiling, replication and transcription.
We will continue developing novel computational methods for sub-particle refinement and nucleic acid
modeling, specifically cryoID, an integrative software package that allows near-atomic resolution cryoEM
structures from many complexes in enriched cellular milieu to be determined, identified, and atomically
modeled (Aim #1); sub-particle reconstructions and refinement for in situ atomic structures in large deformable
or intrinsically structurally heterogeneous complexes such as those in large enveloped viruses and native
cellular complexes (e.g., helical assemblies) (Aim #2); modeling genome structures in both RNA and DNA
viruses, as well as cellular transcriptional/replicative complexes (Aim #3); and validate these new methods for
atomic structure determination by application to red blood cell proteome, translocon bacteriocin nano-machines
and membrane protein complexes, helical filamentous cellular (e.g., actin and axoneme) and viral assemblies
and genome structures inside a number of ssRNA, dsRNA and dsDNA viruses (Aim #4).
 A successful outcome of this renewal project will further advance cryoEM in structural studies of large
complexes and w...

## Key facts

- **NIH application ID:** 10813503
- **Project number:** 3R01GM071940-15S1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **Principal Investigator:** Z Hong ZHOU
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $85,328
- **Award type:** 3
- **Project period:** 2006-05-01 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10813503

## Citation

> US National Institutes of Health, RePORTER application 10813503, High-Resolution CryoEM Reconstruction of Large Complexes (3R01GM071940-15S1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10813503. Licensed CC0.

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