Cryo-EM resources

Facility Instruments information

Titan Krios Falcon4i (EFTEM mode):

  • magnification 53,000 – 2.40 Angstrom/pixel
  • magnification 64,000 – 1.96 Angstrom/pixel
  • magnification 81,000 – 1.514* Angstrom/pixel
  • magnification 105,000 – 1.186* Angstrom/pixel
  • magnification 130,000 – 0.929* Angstrom/pixel
  • magnification 165,000 – 0.729* Angstrom/pixel
  • magnification 215,000 – 0.5708* Angstrom/pixel
  • magnification 270,000 – 0.4550* Angstrom/pixel

    Titan Krios Falcon3 (TEM mode):

    • magnification 37,000 – 2.26 Angstrom/pixel
    • magnification 47,000 – 1.75 Angstrom/pixel
    • magnification 59,000 – 1.40 Angstrom/pixel
    • magnification 75,000 – 1.09 Angstrom/pixel
    • magnification 96,000 – 0.85 Angstrom/pixel
    • magnification 120,000 – 0.67 Angstrom/pixel

    Talos Arctica Falcon 3 (TEM mode only):

    • magnification 17,500 – 6.0 Angstrom/pixel
    • magnification 28,000 – 3.7 Angstrom/pixel
    • magnification 36,000 – 2.9 Angstrom/pixel
    • magnification 45,000 – 2.3 Angstrom/pixel
    • magnification 57,000 – 1.82 Angstrom/pixel
    • magnification 73,000 – 1.43* Angstrom/pixel
    • magnification 92,000 – 1.13* Angstrom/pixel
    • magnification 120,000 – 0.89 Angstrom/pixel
    • magnification 150,000 – 0.70 Angstrom/pixel

    *pixel size was confirmed by collecting high-resolution EM data and comparing the obtained reconstruction to the corresponding high-resolution X-ray structure.

    Approximate data collection rates (movies/hour):

    • Talos Arctica on Falcon 3 detector:
      • in linear mode – 50 movies/hour
      • in counting mode – 22 movies/hour
    • Titan Krios on Falcon 4i detector in counting mode with AFIS* and FFI**:
      • 300 movies/hour (R0.6/1.0; 1 exposure/hole)
      • 450 movies/hour (R1.2/1.3; 3 exposures/hole)
      • 500 movies/hour (R1.2/1.3; 4 exposures/hole)
      • 490 movies/hour (R2/2; 10 exposures/hole)

    *AFIS - Aberration-Free Image Shift (AFIS) allows the use of "beam shifts" instead of "stage shifts" during the data collection, thus drastically increasing throughput. The disadvantage is the less accurate positioning of the exposure area within the holes. 
    *FFI - Fringe-free imaging (FFI) minimises the illuminated area and damages the sample less, allowing more images to be captured within a single foil hole.

    Gain reference file:

    • Falcon 4i camera: The gain reference file can be found inside the movies directory, it has an extension .gain and is in TIFF format. You don't need to change the orientation of the gain reference. To convert .gain to .mrc use the following command "tif2mrc gain-reference-file-name.gain gain-reference-file-name.mrc".
    • Falcon 3 camera: The data is collected as gain-corrected files.
    • K3 camera: The facility staff will provide the gain reference file. When correcting gain using the supplied gain reference file, use "Flip Y axis" option in your processing software.

    Falcon4i MTF file:

    • The image sensors' modulation transfer function (MTF) is crucial to evaluating the overall imaging system quality. The image sensor MTF reflects the spatial frequency response of the sensor. For Falcon4i camera, use the file provided by RELION: https://github.com/3dem/relion/blob/master/data/mtf_falcon4EC_300kV.star

    Objective apertures:

    • The 100 μm objective aperture would allow for transmission of information up to ~1.4 Å
    • The 70 μm aperture would truncate information at the ~2 Å limit

    Cryo-EM Forum @ Biochemistry

    To promote the use and expand our knowledge of the Cryo-EM technique, we’ve created a Cryo-EM Forum @ Biochemistry – a series of informal seminars with invited experts in the area of Cryo-EM.

    Organising team: 

    Next Talk:

    TBA

    Past Talks:

    2023, May 19:
    “Relion/cryoSPARC processing” presented by Dr Andrzej Szewczak-Harris, Cryo-EM Facility, University of Cambridge, UK.

    2023, April 19:
    “Meet The Cryo-Electron Microscopy Facility” presented by Dr Dima Chirgadze, Cryo-EM Facility Manager, University of Cambridge, UK.

    2019, November 22:
    “In situ liquid phase electron microscopy, 3D imaging and He ion microscopy” presented by Dr Richard Langford, Head of Cavendish Electron Microscopy Suite, University of Cambridge, UK.

    2019, November 8:
    “The structure of human thyroglobulin” presented by Dr Francesca Coscia, MRC Laboratory of Molecular Biology, Cambridge, UK.

    2019, April 10:
    “Model building, refinement and validation in CCP-EM” presented by Dr Colin Palmer, CCP-EM Development Team, Rutherford Appleton Laboratory, Didcot, UK.

    2019, February 27:
    “Micro Electron Diffraction in a Cryo Electron Microscope: A powerful tool for protein and small molecule structure determination.” presented by Dr Abhay Kotecha, Materials and Structural Analysis Division, Thermo Fisher Scientific

    2019, January 30:
    1) “chameleon: next generation cryoEM sample preparation based on Spotiton” presented by Dr Michele Darrow of TTP Labtech
    2) “Cryo-EM Facility update” presented by Dr Dima Chirgadze of Department of Biochemistry, University of Cambridge

    2018, April 25:
    “Cryo-EM Facility update” presented by Dr Dima Chirgadze of Department of Biochemistry, University of Cambridge

    2018, April 18:
    “Electron cryo-microscopy of protein transport and assembly machines” presented by Dr Vicki Gold,  Living Systems Institute (LSI) Exeter.

    2017, August 10:
    “Subtomogram analysis of the 8(!) kDa gas vesicle protein A” presented by Dr Daniel Bollschweiler of Department of Biochemistry, University of Cambridge.

    2017, June 6:
    “Studying the evolution of macromolecular machines using high-throughput electron cryo-tomography” presented by Dr Morgan Beeby of Imperial College London.

    2016, December  6:
    “Single-particle CryoEM specimen preparation and data collection — improving on the way” presented by Dr Shaoxia Chen of MRC LMB.

    2016, November 3:
    “Cryo-electron microscopy with the Volta phase plate” presented by Dr Maryam Khoshouei of Max Planck Institute of Biochemistry.

    2016, October 19:
    “Optimal single particle cryoEM data collection: microscope, detector, and dose considerations”. Presented by Dr Kasim Sader of FEI

    2016, September 13:
    “Reducing specimen movement to improve electron cryomicroscopy” presented by Dr Christopher Russo of MRC-LMB.

    2016, July 27:
    “Sample preparation for Cryo-EM” by Dr Jamie Blaza of MRC-MBU
    “”Terms and Conditions” of Cryo-EM” by Dr Dima Chirgadze of Department of Biochemistry.

    2016, July 6:
    “Titan Krios at The Nanoscience Centre. What to do with your Sundays. Access for University users”  by Dr Dima Chirgadze of Department of Biochemistry.

    2016, June 24:
    First "Cryo-EM Forum at Biochemistry" Meeting

    External links

    For those who want to know more about cryo-electron microscopy, we would like to recommend the following resources.