# Mass Spectrometry of Protein Assemblies

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 2020 · $348,231

## Abstract

PROJECT SUMMARY/ABSTRACT
The overall goal of our continuing research program is to develop advanced technologies based on electrospray
ionization (ESI) with mass spectrometry (MS) to support structural biology efforts. The role of protein assemblies
in normal cellular processes and diseases warrants a practical and sensitive method for their study. The
structural determination of protein complexes can play an important role in the fundamental understanding of
biochemical pathways. New techniques based on native mass spectrometry (i.e., the measurement of
biomolecules in their native solution environment to preserve interactions with ligands and other molecules) will
be advanced to facilitate the characterization of protein assemblies. Improved methods for measuring large
protein complexes (including >0.5 MDa) will be developed. Native protein separations for subsequent analysis
by native MS will be advanced. Experimental MS protocols for difficult-to-characterize membrane proteins will
be developed. Enhancing multiple charging generated by ESI increases the efficiency for top-down MS (the
direct fragmentation of intact gas-phase large molecules to generate structure-informative product ions) and
native MS; we will identify new charge enhancing agents, and we will apply these new reagents for top-down
MS and membrane protein MS. With high-resolution Fourier transform-ion cyclotron resonance mass
spectrometry, enhanced native top-down MS methods will be developed to obtain structurally-relevant
information for large protein complexes. Methods incorporating UV photodissociation, electron capture
dissociation, and electron ionization dissociation will be developed and tested for their efficiency to generate
sequence information from large protein complexes and membrane proteins. Strategies for determining collision
cross sections will be improved. These advanced tools will be applied to characterize complexes of biological
importance where high-resolution structures are unavailable, including G-coupled protein receptors (GPCRs).
Our experimental strategies are broadly applicable to be integrated with different types of biophysical techniques;
such integration will allow the study of large and complex molecular machines in greater detail, providing insight
into the functional dynamics of the system. Native top-down MS will be a promising approach to advance
structural biology and hasten drug discovery and development.

## Key facts

- **NIH application ID:** 9955264
- **Project number:** 5R01GM103479-16
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **Principal Investigator:** Joseph A Loo
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $348,231
- **Award type:** 5
- **Project period:** 2004-07-15 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9955264

## Citation

> US National Institutes of Health, RePORTER application 9955264, Mass Spectrometry of Protein Assemblies (5R01GM103479-16). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9955264. Licensed CC0.

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