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3D Cryo-Electron Microscopy

Investigators: Carlos Óscar Sánchez Sorzano, Slavica Jonić, Michael Unser

Main Contributions

We have introduced the Spectral-Signal-to-Noise Ratio (SSNR) criterion for determining the resolution of 2D (by correlation averaging) and 3D reconstructions (by electron tomography) of macro molecules.

We have also proposed two complementary algorithms for refining the angular and translational parameters of the projection data used for 3D reconstruction. The first one is wavelet-based and performs a multiscale matching against a gallery of images, while the other one uses iterative 2D-to-3D registration.

Collaborations: Dr. Philippe Thévenaz, Drs. Catherine El-Bez and Sacha De Carlo (LAU, Uni Lausanne), Dr. Benes L. Trus (NIH, USA)

Period: 2002-2006

Major Publications


M. Unser, C.Ó. Sánchez Sorzano, P. Thévenaz, S. Jonić, C. El-Bez, S. De Carlo, J.F. Conway, B.L. Trus, "Spectral Signal-to-Noise Ratio and Resolution Assessment of 3D Reconstructions," Journal of Structural Biology, vol. 149, no. 3, pp. 243-255, March 2005.


C.Ó. Sánchez Sorzano, S. Jonić, C. El-Bez, J.M. Carazo, S. De Carlo, P. Thévenaz, M. Unser, "A Multiresolution Approach to Orientation Assignment in 3D Electron Microscopy of Single Particles," Journal of Structural Biology, vol. 146, no. 3, pp. 381-392, June 2004.


M. Unser, B.L. Trus, A.C. Steven, "A New Resolution Criterion Based on Spectral Signal-To-Noise Ratios," Ultramicroscopy, vol. 23, no. 1, pp. 39-51, 1987.


M. Unser, B.L. Trus, J.A. Frank, A.C. Steven, "The Spectral Signal-To-Noise Ratio Resolution Criterion: Computational Efficiency and Statistical Precision," Ultramicroscopy, vol. 30, no. 3, pp. 429-434, July-August 1989.


M. Unser, A.C. Steven, B.L. Trus, "Odd Men Out: A Quantitative Objective Procedure for Identifying Anomalous Members of a Set of Noisy Images of Ostensibly Identical Specimens," Ultramicroscopy, vol. 19, no. 4, pp. 337-347, 1986.


A.C. Steven, B.L. Trus, J.V. Maizel, M. Unser, D.A. Parry, J.S. Wall, J.F. Hainfeld, F.W. Studier, "Molecular Substructure of a Viral Receptor-Recognition Protein. The gp17 Tail-Fiber of Bacteriophage T7," Journal of Molecular Biology, vol. 200, no. 2, pp. 351-365, March 1988.


M. Unser, B.L. Trus, A.C. Steven, "Normalization Procedures and Factorial Representations for Classification of Correlation-Aligned Images: A Comparative Study," Ultramicroscopy, vol. 30, no. 3, pp. 299-310, July-August 1989.

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