WikiSysop: Created page with "== Citation == J. Remis et al., “Cryo-EM phase-plate images reveal unexpected levels of apparent specimen damage,” Journal of Structural Biology, p. 108150, 2024. == Abstract == Apoferritin (apoF) is commonly used as a test specimen in single-particle electron cryo-microscopy (cryo-EM), since it consistently produces density maps that go to 3 Å resolution or higher. When we imaged apoF with a laser phase plate (LPP), however, we observed more severe particle-to-p..."

2024-12-12T08:35:55Z

Created page with "== Citation == J. Remis et al., “Cryo-EM phase-plate images reveal unexpected levels of apparent specimen damage,” Journal of Structural Biology, p. 108150, 2024. == Abstract == Apoferritin (apoF) is commonly used as a test specimen in single-particle electron cryo-microscopy (cryo-EM), since it consistently produces density maps that go to 3 Å resolution or higher. When we imaged apoF with a laser phase plate (LPP), however, we observed more severe particle-to-p..."

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== Citation ==

J. Remis et al., “Cryo-EM phase-plate images reveal unexpected levels of apparent specimen damage,” Journal of Structural Biology, p. 108150, 2024.

== Abstract ==

Apoferritin (apoF) is commonly used as a test specimen in single-particle electron cryo-microscopy (cryo-EM),
since it consistently produces density maps that go to 3 Å resolution or higher. When we imaged apoF with a laser
phase plate (LPP), however, we observed more severe particle-to-particle variation in the images than we had
previously thought to exist. Similarly, we found that images of ribulose bisphosphate carboxylase/oxygenase
(rubisco) also exhibited a much greater amount of heterogeneity than expected. By comparison to simulations of
images, we verified that the heterogeneity is not explained by the known features of the LPP, shot noise, or
differences in particle orientation. We also demonstrate that our specimens are comparable to those previously
used in the literature, based on using the final-reconstruction resolution as the metric for evaluation. All of this
leads us to the hypothesis that the heterogeneity is due to damage that has occurred either during purification of
the specimen or during preparation of the grids. It is not, however, our goal to explain the causes of heterogeneity;
rather, we report that using the LPP has made the apparent damage too obvious to be ignored. In hindsight,
similar heterogeneity can be seen in images of apoF and the 20S proteasome which others had recorded
with a Volta phase plate. We therefore conclude that the increased contrast of phase-plate images (at low spatial
frequencies) should also make it possible to visualize, on a single-particle basis, various forms of biologically
functional heterogeneity in structure that had previously gone unnoticed.

== Keywords ==

== Links ==

https://www.sciencedirect.com/science/article/pii/S104784772400090X

== Related software ==

== Related methods ==

== Comments ==

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