Electron counting and beam-induced motion correction enable near-atomic-resolution single-particle cryo-EM
Xueming Li,Paul Mooney,Shawn Q. Zheng,Shawn Q. Zheng,Christopher R. Booth,Michael B. Braunfeld,Michael B. Braunfeld,Sander Gubbens,David A. Agard,David A. Agard,Yifan Cheng +10 more
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TLDR
This approach determined a 3.3-Å-resolution structure of an ∼700-kDa protein with D7 symmetry, the Thermoplasma acidophilum 20S proteasome, showing clear side-chain density and greatly enhances image quality and data acquisition efficiency.Abstract:
In recent work with large high-symmetry viruses, single-particle electron cryomicroscopy (cryo-EM) has achieved the determination of near-atomic-resolution structures by allowing direct fitting of atomic models into experimental density maps. However, achieving this goal with smaller particles of lower symmetry remains challenging. Using a newly developed single electron-counting detector, we confirmed that electron beam-induced motion substantially degrades resolution, and we showed that the combination of rapid readout and nearly noiseless electron counting allow image blurring to be corrected to subpixel accuracy, restoring intrinsic image information to high resolution (Thon rings visible to ∼3 A). Using this approach, we determined a 3.3-A-resolution structure of an ∼700-kDa protein with D7 symmetry, the Thermoplasma acidophilum 20S proteasome, showing clear side-chain density. Our method greatly enhances image quality and data acquisition efficiency-key bottlenecks in applying near-atomic-resolution cryo-EM to a broad range of protein samples.read more
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Structure of transcribing mammalian RNA polymerase II
TL;DR: The results define the structure of mammalian Pol II in its functional state, indicate that previous crystallographic analysis of yeast Pol II is relevant for understanding gene transcription in all eukaryotes, and provide a starting point for a mechanistic analysis of human transcription.
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2.8 Å resolution reconstruction of the Thermoplasma acidophilum 20S proteasome using cryo-electron microscopy
TL;DR: The results described in this manuscript demonstrate that single particle cryoEM is capable of competing with X-ray crystallography for determination of protein structures of suitable quality for rational drug design.
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Structure of the native Sec61 protein-conducting channel
Stefan Pfeffer,Laura Burbaum,Pia Unverdorben,Markus Pech,Yuxiang Chen,Richard Zimmermann,Roland Beckmann,Friedrich Förster +7 more
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Modular Assembly of the Bacterial Large Ribosomal Subunit
Joseph H. Davis,Yong Zi Tan,Bridget Carragher,Clinton S. Potter,Dmitry Lyumkis,James R. Williamson +5 more
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Structural organization of the dynein-dynactin complex bound to microtubules
TL;DR: Using electron microscopy, the organization of native bovine dynein, dynactin and the dyne in–dynactin–microtubule quaternary complex is determined and it is determined that in the microtubule-bound complex, the Dynein motor domains are positioned for processive unidirectional movement.
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