The Experts below are selected from a list of 13419 Experts worldwide ranked by ideXlab platform
David A Agard - One of the best experts on this subject based on the ideXlab platform.
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evaluation of super resolution performance of the k2 Electron Counting camera using 2d crystals of aquaporin 0
Journal of Structural Biology, 2015Co-Authors: Polin Chiu, Brian C Beckett, Axel F Brilot, Nikolaus Grigorieff, David A Agard, Yifan Cheng, Thomas WalzAbstract:The K2 Summit camera was initially the only commercially available direct Electron detection camera that was optimized for high-speed Counting of primary Electrons and was also the only one that implemented centroiding so that the resolution of the camera can be extended beyond the Nyquist limit set by the physical pixel size. In this study, we used well-characterized two-dimensional crystals of the membrane protein aquaporin-0 to characterize the performance of the camera below and beyond the physical Nyquist limit and to measure the influence of Electron dose rate on image amplitudes and phases.
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influence of Electron dose rate on Electron Counting images recorded with the k2 camera
Journal of Structural Biology, 2013Co-Authors: Shawn Q Zheng, David A Agard, Kiyoshi Egami, Yifan ChengAbstract:A recent technological breakthrough in Electron cryomicroscopy (cryoEM) is the development of direct Electron detection cameras for data acquisition. By bypassing the traditional phosphor scintillator and fiber optic coupling, these cameras have greatly enhanced sensitivity and detective quantum efficiency (DQE). Of the three currently available commercial cameras, the Gatan K2 Summit was designed specifically for Counting individual Electron events. Counting further enhances the DQE, allows for practical doubling of detector resolution and eliminates noise arising from the variable deposition of energy by each primary Electron. While Counting has many advantages, underCounting of Electrons happens when more than one Electron strikes the same area of the detector within the analog readout period (coincidence loss), which influences image quality. In this work, we characterized the K2 Summit in Electron Counting mode, and studied the relationship of dose rate and coincidence loss and its influence on the quality of counted images. We found that coincidence loss reduces low frequency amplitudes but has no significant influence on the signal-to-noise ratio of the recorded image. It also has little influence on high frequency signals. Images of frozen hydrated archaeal 20S proteasome (~700 kDa, D7 symmetry) recorded at the optimal dose rate retained both high-resolution signal and low-resolution contrast and enabled calculating a 3.6 A three-dimensional reconstruction from only 10,000 particles.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Paul Mooney, David A Agard, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander Gubbens, Yifan ChengAbstract:In recent work with large high symmetry viruses, single particle Electron cryomicroscopy (cryoEM) has reached the milestone of determining 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 extraordinarily challenging. Using a newly developed single Electron Counting detector, we confirm that Electron beam induced motion significantly degrades resolution and, importantly, show how the combination of rapid readout and nearly noiseless Electron Counting allow image blurring to be corrected to subpixel accuracy. Thus, intrinsic image information can be restored to high resolution (Thon rings visible to ~3 A). Using this approach we determined a 3.3 A resolution structure of a ~700 kDa protein with D7 symmetry showing clear side chain density. Our method greatly enhances image quality and data acquisition efficiency - key bottlenecks in applying near atomic resolution cryoEM to a broad range of protein samples.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Xueming Li, David A Agard, Paul Mooney, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander GubbensAbstract:The combination of a direct Electron-detection camera that can count individual Electrons and an algorithm for correcting for beam-induced motion in cryo-EM will facilitate determination of three-dimensional structures of smaller, lower-symmetry macromolecular complexes to higher resolution than previously possible.
Shawn Q Zheng - One of the best experts on this subject based on the ideXlab platform.
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influence of Electron dose rate on Electron Counting images recorded with the k2 camera
Journal of Structural Biology, 2013Co-Authors: Shawn Q Zheng, David A Agard, Kiyoshi Egami, Yifan ChengAbstract:A recent technological breakthrough in Electron cryomicroscopy (cryoEM) is the development of direct Electron detection cameras for data acquisition. By bypassing the traditional phosphor scintillator and fiber optic coupling, these cameras have greatly enhanced sensitivity and detective quantum efficiency (DQE). Of the three currently available commercial cameras, the Gatan K2 Summit was designed specifically for Counting individual Electron events. Counting further enhances the DQE, allows for practical doubling of detector resolution and eliminates noise arising from the variable deposition of energy by each primary Electron. While Counting has many advantages, underCounting of Electrons happens when more than one Electron strikes the same area of the detector within the analog readout period (coincidence loss), which influences image quality. In this work, we characterized the K2 Summit in Electron Counting mode, and studied the relationship of dose rate and coincidence loss and its influence on the quality of counted images. We found that coincidence loss reduces low frequency amplitudes but has no significant influence on the signal-to-noise ratio of the recorded image. It also has little influence on high frequency signals. Images of frozen hydrated archaeal 20S proteasome (~700 kDa, D7 symmetry) recorded at the optimal dose rate retained both high-resolution signal and low-resolution contrast and enabled calculating a 3.6 A three-dimensional reconstruction from only 10,000 particles.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Paul Mooney, David A Agard, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander Gubbens, Yifan ChengAbstract:In recent work with large high symmetry viruses, single particle Electron cryomicroscopy (cryoEM) has reached the milestone of determining 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 extraordinarily challenging. Using a newly developed single Electron Counting detector, we confirm that Electron beam induced motion significantly degrades resolution and, importantly, show how the combination of rapid readout and nearly noiseless Electron Counting allow image blurring to be corrected to subpixel accuracy. Thus, intrinsic image information can be restored to high resolution (Thon rings visible to ~3 A). Using this approach we determined a 3.3 A resolution structure of a ~700 kDa protein with D7 symmetry showing clear side chain density. Our method greatly enhances image quality and data acquisition efficiency - key bottlenecks in applying near atomic resolution cryoEM to a broad range of protein samples.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Xueming Li, David A Agard, Paul Mooney, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander GubbensAbstract:The combination of a direct Electron-detection camera that can count individual Electrons and an algorithm for correcting for beam-induced motion in cryo-EM will facilitate determination of three-dimensional structures of smaller, lower-symmetry macromolecular complexes to higher resolution than previously possible.
Michael B Braunfeld - One of the best experts on this subject based on the ideXlab platform.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Paul Mooney, David A Agard, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander Gubbens, Yifan ChengAbstract:In recent work with large high symmetry viruses, single particle Electron cryomicroscopy (cryoEM) has reached the milestone of determining 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 extraordinarily challenging. Using a newly developed single Electron Counting detector, we confirm that Electron beam induced motion significantly degrades resolution and, importantly, show how the combination of rapid readout and nearly noiseless Electron Counting allow image blurring to be corrected to subpixel accuracy. Thus, intrinsic image information can be restored to high resolution (Thon rings visible to ~3 A). Using this approach we determined a 3.3 A resolution structure of a ~700 kDa protein with D7 symmetry showing clear side chain density. Our method greatly enhances image quality and data acquisition efficiency - key bottlenecks in applying near atomic resolution cryoEM to a broad range of protein samples.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Xueming Li, David A Agard, Paul Mooney, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander GubbensAbstract:The combination of a direct Electron-detection camera that can count individual Electrons and an algorithm for correcting for beam-induced motion in cryo-EM will facilitate determination of three-dimensional structures of smaller, lower-symmetry macromolecular complexes to higher resolution than previously possible.
Yifan Cheng - One of the best experts on this subject based on the ideXlab platform.
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evaluation of super resolution performance of the k2 Electron Counting camera using 2d crystals of aquaporin 0
Journal of Structural Biology, 2015Co-Authors: Polin Chiu, Brian C Beckett, Axel F Brilot, Nikolaus Grigorieff, David A Agard, Yifan Cheng, Thomas WalzAbstract:The K2 Summit camera was initially the only commercially available direct Electron detection camera that was optimized for high-speed Counting of primary Electrons and was also the only one that implemented centroiding so that the resolution of the camera can be extended beyond the Nyquist limit set by the physical pixel size. In this study, we used well-characterized two-dimensional crystals of the membrane protein aquaporin-0 to characterize the performance of the camera below and beyond the physical Nyquist limit and to measure the influence of Electron dose rate on image amplitudes and phases.
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influence of Electron dose rate on Electron Counting images recorded with the k2 camera
Journal of Structural Biology, 2013Co-Authors: Shawn Q Zheng, David A Agard, Kiyoshi Egami, Yifan ChengAbstract:A recent technological breakthrough in Electron cryomicroscopy (cryoEM) is the development of direct Electron detection cameras for data acquisition. By bypassing the traditional phosphor scintillator and fiber optic coupling, these cameras have greatly enhanced sensitivity and detective quantum efficiency (DQE). Of the three currently available commercial cameras, the Gatan K2 Summit was designed specifically for Counting individual Electron events. Counting further enhances the DQE, allows for practical doubling of detector resolution and eliminates noise arising from the variable deposition of energy by each primary Electron. While Counting has many advantages, underCounting of Electrons happens when more than one Electron strikes the same area of the detector within the analog readout period (coincidence loss), which influences image quality. In this work, we characterized the K2 Summit in Electron Counting mode, and studied the relationship of dose rate and coincidence loss and its influence on the quality of counted images. We found that coincidence loss reduces low frequency amplitudes but has no significant influence on the signal-to-noise ratio of the recorded image. It also has little influence on high frequency signals. Images of frozen hydrated archaeal 20S proteasome (~700 kDa, D7 symmetry) recorded at the optimal dose rate retained both high-resolution signal and low-resolution contrast and enabled calculating a 3.6 A three-dimensional reconstruction from only 10,000 particles.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Paul Mooney, David A Agard, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander Gubbens, Yifan ChengAbstract:In recent work with large high symmetry viruses, single particle Electron cryomicroscopy (cryoEM) has reached the milestone of determining 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 extraordinarily challenging. Using a newly developed single Electron Counting detector, we confirm that Electron beam induced motion significantly degrades resolution and, importantly, show how the combination of rapid readout and nearly noiseless Electron Counting allow image blurring to be corrected to subpixel accuracy. Thus, intrinsic image information can be restored to high resolution (Thon rings visible to ~3 A). Using this approach we determined a 3.3 A resolution structure of a ~700 kDa protein with D7 symmetry showing clear side chain density. Our method greatly enhances image quality and data acquisition efficiency - key bottlenecks in applying near atomic resolution cryoEM to a broad range of protein samples.
Paul Mooney - One of the best experts on this subject based on the ideXlab platform.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Paul Mooney, David A Agard, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander Gubbens, Yifan ChengAbstract:In recent work with large high symmetry viruses, single particle Electron cryomicroscopy (cryoEM) has reached the milestone of determining 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 extraordinarily challenging. Using a newly developed single Electron Counting detector, we confirm that Electron beam induced motion significantly degrades resolution and, importantly, show how the combination of rapid readout and nearly noiseless Electron Counting allow image blurring to be corrected to subpixel accuracy. Thus, intrinsic image information can be restored to high resolution (Thon rings visible to ~3 A). Using this approach we determined a 3.3 A resolution structure of a ~700 kDa protein with D7 symmetry showing clear side chain density. Our method greatly enhances image quality and data acquisition efficiency - key bottlenecks in applying near atomic resolution cryoEM to a broad range of protein samples.
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Electron Counting and beam induced motion correction enable near atomic resolution single particle cryo em
Nature Methods, 2013Co-Authors: Xueming Li, David A Agard, Paul Mooney, Shawn Q Zheng, Christopher R Booth, Michael B Braunfeld, Sander GubbensAbstract:The combination of a direct Electron-detection camera that can count individual Electrons and an algorithm for correcting for beam-induced motion in cryo-EM will facilitate determination of three-dimensional structures of smaller, lower-symmetry macromolecular complexes to higher resolution than previously possible.