AbstractHere we show that single particle charge-detection mass spectrometry (CD-MS) can be performed on a ubiquitous Orbitrap mass analyser and applied to the analysis of high-mass (megadalton) heterogeneous biomolecular assemblies. We demonstrate that single particle high-mass ions can survive in the Orbitrap for seconds, whereby their measured signal amplitudes scale linearly with charge state over the entire m/z range. Orbitrap based single particle CD-MS can be used to resolve mixed ion populations, accurately predict charge states, and consequently also the mass of the ions. We successfully applied CD-MS to challenging natural and biotherapeutic protein assemblies, such as IgM oligomers, designed protein nano-cages, ribosome particles and intact, empty- and genome-loaded Adeno-associated virus particles. Single particle CD-MS combined with native MS on existing Orbitrap platforms will greatly expand its application, especially in the mass analysis of megadalton heterogeneous biomolecular assemblies.
Acquiring Structural Information on Virus Particles with Charge Detection Mass Spectrometry