Single molecule resolution from just nanograms
of sample in minutes
Cryo-electron microscopy (cryo-EM) is a powerful tool for creating high resolution 3D protein structures. To achieve the highest resolution 3D model, a monodisperse sample and homogenous EM grid distribution is needed. Screening of various buffers and purification conditions is a critical step in the cryo-EM workflow. Choosing screening technologies that provide single molecule resolution, a rapid time to answer, and use minimal amounts of sample will help improve cryo-EM workflow efficiency.
Single particle measurement ensures sample homogeneity
Sending substandard samples for cryo-EM not only wastes time and money but also results in unsolved high resolution structures. For cryo-EM sample optimization and screening, single particle measurement provides the resolution needed for visibility of small population differences to ensure monodispersity and sample homogeneity.
Many tools can be used to assess monodispersity. Some provide bulk sample information while others provide information related to single particles.
Single particle measurement tools include negative stain electron microscopy (nsEM) and mass photometry, and provide information related to individual species in a sample. Conversely, dynamic light scattering (DLS), size exclusion chromatography (SEC), and SDS-PAGE provide averaged (bulk) sample information.
When working to ensure all particles in a sample are roughly the same size, shape, and mass, a single particle measurement tool can provide superior understanding of sample readiness.
Save sample while finding the right conditions quickly
While negative stain EM is the gold standard screening tool for cryo-EM, it also has limitations in expense, non-native heavy metal stain requirements, and long analysis time. Thus, it’s utility as a quick screening tool can sometimes be limited.
Mass photometry can be complementary to negative-stain EM as it is compatible with most aqueous buffers and many membrane mimetic systems, so it is possible to analyze biomolecules, including membrane proteins and macromolecular complexes, in their native states.
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Mass photometry method offers a readout time of less than 5 minutes with low sample requirements (10uL of sample at nanomolar concentration), thus making it a desirable technique during early structure stability optimization and buffer condition screening before proceeding to negative-stain EM and cryo-EM.
Watch the webinar below to hear Dr. Adar Sonn Segev from the Physical and Theoretical Chemistry Lab at the University of Oxford describe how mass photometry provides quantitative information on sample heterogeneity using minimal volumes with molecular resolution. She will also discuss how this approach applies to several different workflows, including screening before cryo-EM, comparing it to standard tools for assessing sample purity.
Overview:
Watch the webinar below to hear Dr. Adar Sonn Segev from the Physical and Theoretical Chemistry Lab at the University of Oxford describe how mass photometry provides quantitative information on sample heterogeneity using minimal volumes with molecular resolution.
Speaker: Adar Sonn Segev, Physical and Theoretical Chemistry Laboratory, University of Oxford
Duration: 39 minutes
​Key Takeaways:
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Learn how mass photometry can be your ideal pre-cryo-EM screening solution by providing single molecule resolution using just nanograms of sample, in minutes.
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Discuss how this approach applies to several different workflows, including screening before cryo-EM, comparing it to standard tools for assessing sample purity.
Mass photometry
Single molecule resolution with just nanograms of sample in minutes
Single molecule resolution
Single particle measurements with 25-60 kDa resolution
Wide dynamic range
Single particle measurements in the 30 kDa to 5 MDa range
Fast time to answer
Data acquisition and analysis all in
less than 5 minutes
Low affinity complexes
Rapid dilution microfluidics system for measurement of low affinity complexes
Low sample consumption
Less than 500 ng of sample at nanomolar concentrations
Fill out the form to access the webinar
In this webinar, you'll learn how mass photometry can be your ideal sample optimization and screening tool, providing single molecule resolution using just nanograms of sample in minutes.