National Institutes of Health/National Institute of General Medical Sciences
U24 GM116789
米国
National Institutes of Health/National Institute of Neurological Disorders and Stroke
1U01NS110437
米国
National Institutes of Health/National Institute Of Allergy and Infectious Diseases
R01 AI111095
米国
National Institutes of Health/National Institute of Neurological Disorders and Stroke
R01 NS050227
米国
引用
ジャーナル: J Struct Biol / 年: 2019 タイトル: Sub-3 Å apoferritin structure determined with full range of phase shifts using a single position of volta phase plate. 著者: Kunpeng Li / Chen Sun / Thomas Klose / Jose Irimia-Dominguez / Frank S Vago / Ruben Vidal / Wen Jiang / 要旨: Volta Phase Plate (VPP) has become an invaluable tool for cryo-EM structural determination of small protein complexes by increasing image contrast. Currently, the standard protocol of VPP usage ...Volta Phase Plate (VPP) has become an invaluable tool for cryo-EM structural determination of small protein complexes by increasing image contrast. Currently, the standard protocol of VPP usage periodically changes the VPP position to a fresh spot during data collection. Such a protocol was to target the phase shifts to a relatively narrow range (around 90°) based on the observations of increased phase shifts and image blur associated with more images taken with a single VPP position. Here, we report a 2.87 Å resolution structure of apoferritin reconstructed from a dataset collected using only a single position of VPP. The reconstruction resolution and map density features are nearly identical to the reconstruction from the control dataset collected with periodic change of VPP positions. Further experiments have verified that similar results, including a 2.5 Å resolution structure, could be obtained with a full range of phase shifts, different spots of variable phase shift increasing rates, and at different ages of the VPP post-installation. Furthermore, we have found that the phase shifts at low resolutions, probably related to the finite size of the Volta spots, could not be correctly modeled by current CTF model using a constant phase shift at all frequencies. In dataset III, severe beam tilt issue was identified but could be computationally corrected with iterative refinements. The observations in this study may provide new insights into further improvement of both the efficiency and robustness of VPP, and to help turn VPP into a plug-and-play device for high-resolution cryo-EM.
EMPIAR-10263 (タイトル: Sub-3 Å Apoferritin Structure Determined With Full Range of Phase Shifts Using A Single Position Of Volta Phase Plate Data size: 778.8 Data #1: Unaligned multi-frame movie of apoferritin Dataset I [micrographs - multiframe] Data #2: Unaligned multi-frame movie of apoferritin Dataset II [micrographs - multiframe] Data #3: Unaligned multi-frame movie of apoferritin Dataset III [micrographs - multiframe] Data #4: Unaligned multi-frame movie of apoferritin Dataset IV [micrographs - multiframe])