Unveiling ground truths from data containing vague truths: the story of cryo-electron microscopy
- 2019-12-02 (Mon.), 10:00 AM
- R6005, Research Center for Environmental Changes Building
- Prof. Wei-Hau Chang
- Institute of Chemistry, Academia Sinica
Abstract
Detailed interactions between biological molecules are the fundamental to life, of which the compromise may cause diseases. These interactions can be exemplified by famous antibody-antigen interactions and many others. Direct visualization of such interactions at atomic resolution or at the level of chemical bonds have been made possible by protein X-ray crystallography depends on many technical advances in particular, synchrotron radiation and crystallization screen. Recent advance in low temperature electron microscopy (cryo-EM) has fulfilled a long-waited promise that protein structure can be revealed to near atomic resolution in the absence of crystal. This means a structure of a protein in its working conditions is now accessible. However, it has been a mis-concept that these detailed structures are directly available in the raw data that getting a powerful microscope is sufficient. In this talk, I will first brief X-ray crystallography and the ground truths of protein structure established by it. Then I will use a few detailed structures obtained here to illustrate the process of getting ground truths out from the very noisy cryo-EM data through correct “data averaging” through computation. As it is evident, the challenges of data reduction from very noisy data have presented great opportunities for statisticians.