A method for the alignment of heterogeneous macromolecules from electron microscopy.
We propose a feature-based image alignment method for single-particle electron microscopy that is able to accommodate various similarity scoring functions while efficiently sampling the two-dimensional transformational space. We use this image alignment method to evaluate the performance of a scoring function that is based on the Mutual Information (MI) of two images rather than one that is based on the cross-correlation function. We show that alignment using MI for the scoring function has far less model-dependent bias than is found with cross-correlation based alignment. We also demonstrate that MI improves the alignment of some types of heterogeneous data, provided that the signal-to-noise ratio is relatively high. These results indicate, therefore, that use of MI as the scoring function is well suited for the alignment of class-averages computed from single-particle images. Our method is tested on data from three model structures and one real dataset.
Shatsky
Maxim
M
Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA. maxshats@compbio.berkeley.edu
Hall
Richard J
RJ
Brenner
Steven E
SE
Glaeser
Robert M
RM
D000465:Algorithms; D020285:Cryoelectron Microscopy / Q000379:methods; D004256:DNA Polymerase I / Q000648:ultrastructure; D039621:Eukaryotic Initiation Factor-3 / Q000648:ultrastructure; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D046911:Macromolecular Substances; D008854:Microscopy, Electron / Q000379:methods*; D012333:RNA, Messenger / Q000648:ultrastructure; D016601:RNA-Binding Proteins / Q000648:ultrastructure; D012107:Research Design; D054681:Ribosome Subunits, Large, Bacterial / Q000648:ultrastructure; D012270:Ribosomes / Q000648:ultrastructure
D039621:Eukaryotic Initiation Factor-3; D046911:Macromolecular Substances; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D004256:DNA Polymerase I