The One World Cryo-EM seminar series is a platform for discussion of algorithms, computational methods and mathematical problems in cryo-EM.

Online, Every Other Wednesday, at 8am PT / 11am ET/ 4pm BST / 5pm CET / 11pm China.

Registration has changed. For zoom links and announcements, please register to our mailing list. This is a read-only mailing list (users cannot post). Please use your institution/ company email – we approve registrations manually and this helps us know who you are . You may receive an email asking you to confirm your registration, it is important that you click the link, otherwise we will not see your request.

Organizers: Joakim Andén, Dorit Hanein, Roy R. Lederman and Steven J. Ludtke

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One World Cryo-EM will be back in September 2021.

Next Talk

Jensen, Grant

Grant Jensen

Dean, College of Physical and Mathematical Sciences, Brigham Young University

Professor of Biology and Biophysics
California Institute of Technology

Date and time: September 29th, 2021
Wednesday, at 8am PT / 11am ET / 4pm BST / 5pm CEST / 11pm China

For the zoom and links, please join the One World Cryo-EM mailing list.

Montage tomography of cryo-preserved specimens

Ariana Peck, Stephen D. Carter, Huanghao Mai, Songye Chen, Alister Burt, and Grant J. Jensen

Cryo-electron tomography reveals detailed views of macromolecules in situ, but the fields of view can be quite limited. Decades ago, montage tomography methods were developed to large areas of plastic sections, which are less radiation-sensitive than samples in vitreous ice. The dose sensitivity of vitreous samples has been considered prohibitive to montaging approaches, since portions of the sample must be exposed multiple times to allow image stitching. Taking advantage of several technical advances, we have now developed a montage data collection scheme that distributes the extra dose evenly throughout the specimen. We applied this method to image the thin edge of frozen-hydrated HeLa cells, and show that macromolecular details can be resolved across montage tomograms several microns across. Montage cryo-ET could be especially useful for imaging lamellae.

Last Talk

Amit Singer

Amit Singer

Professor of Mathematics at Princeton University

Wilson Statistics: Derivation, Generalization, and Applications to Cryo-EM

Date and time: June 16, 2021

Wednesday, at 8am PT / 11am ET / 3pm GMT / 5pm CET / 11pm China

For the zoom and links, please join the One World Cryo-EM mailing list.
Note that we no longer use the zoom registration system, so old zoom links may not work. The new links will be sent via the mailing list.

The power spectrum of proteins at high frequencies is remarkably well described by the flat Wilson statistics. Wilson statistics therefore plays a significant role in X-ray crystallography and more recently in cryo-EM. Specifically, modern computational methods for three-dimensional map sharpening and atomic modelling of macromolecules by single particle cryo-EM are based on Wilson statistics. In this talk we provide the first rigorous mathematical derivation of Wilson statistics. The derivation pinpoints the regime of validity of Wilson statistics in terms of the size of the macromolecule. Moreover, the analysis naturally leads to generalizations of the statistics to covariance and higher order spectra. These in turn provide theoretical foundation for assumptions underlying the widespread Bayesian inference framework for three-dimensional refinement and for explaining the limitations of autocorrelation based methods in cryo-EM.

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