8EN7

Mouse apoferritin heavy chain without zinc determined using single-particle cryo-EM with Apollo camera.

Summary for 8EN7

• Entry DOI: 10.2210/pdb8en7/pdb
• EMDB information: 28269
• Descriptor: Ferritin heavy chain, N-terminally processed, FE (III) ION (3 entities in total)
• Functional Keywords: bind with iron, metal binding protein
• Biological source: Mus musculus (house mouse)
• Total number of polymer chains: 24
• Total formula weight: 482245.33

Authors

Peng, R.,Fu, X.,Mendez, J.H.,Randolph, P.H.,Bammes, B.,Stagg, S.M. (deposition date: 2022-09-28, release date: 2022-12-21, Last modification date: 2024-06-19)

Primary citation

Peng, R.,Fu, X.,Mendez, J.H.,Randolph, P.S.,Bammes, B.E.,Stagg, S.M.
Characterizing the resolution and throughput of the Apollo direct electron detector.
J Struct Biol X, 7:100080-100080, 2023

PubMed Abstract: Advances in electron detection have been essential to the success of high-resolution cryo-EM structure determination. A new generation of direct electron detector called the Apollo, has been developed by Direct Electron. The Apollo uses a novel event-based MAPS detector custom designed for ultra-fast electron counting. We have evaluated this new camera, finding that it delivers high detective quantum efficiency (DQE) and low coincidence loss, enabling high-quality electron counting data acquisition at up to nearly 80 input electrons per pixel per second. We further characterized the performance of Apollo for single particle cryo-EM on real biological samples. Using mouse apoferritin, Apollo yielded better than 1.9 Å resolution reconstructions at all three tested dose rates from a half-day data collection session each. With longer collection time and improved specimen preparation, mouse apoferritin was reconstructed to 1.66 Å resolution. Applied to a more challenging small protein aldolase, we obtained a 2.24 Å resolution reconstruction. The high quality of the map indicates that the Apollo has sufficiently high DQE to reconstruct smaller proteins and complexes with high-fidelity. Our results demonstrate that the Apollo camera performs well across a broad range of dose rates and is capable of capturing high quality data that produce high-resolution reconstructions for large and small single particle samples.

PubMed: 36578473
DOI: 10.1016/j.yjsbx.2022.100080

Experimental method

ELECTRON MICROSCOPY (1.68 Å)