TY - JOUR T1 - Exploration of parameters in cryo-EM leading to an improved density map of the E. coli ribosome. JF - J Struct Biol Y1 - 2008 A1 - LeBarron, Jamie A1 - Grassucci, Robert A A1 - Shaikh, Tanvir R A1 - Baxter, Bill A1 - Sengupta, Jayati A1 - Frank, Joachim KW - Cryoelectron Microscopy KW - Escherichia coli KW - Image Enhancement KW - Image Processing, Computer-Assisted KW - Ribosomes AB -

A number of image processing parameters in the 3D reconstruction of a ribosome complex from a cryo-EM data set were varied to test their effects on the final resolution. The parameters examined were pixel size, window size, and mode of Fourier amplitude enhancement at high spatial frequencies. In addition, the strategy of switching from large to small pixel size during angular refinement was explored. The relationship between resolution (in Fourier space) and the number of particles was observed to follow a lin-log dependence, a relationship that appears to hold for other data, as well. By optimizing the above parameters, and using a lin-log extrapolation to the full data set in the estimation of resolution from half-sets, we obtained a 3D map from 131,599 ribosome particles at 6.7A resolution (FSC=0.5).

VL - 164 UR - http://www.ncbi.nlm.nih.gov/pubmed/18606549 IS - 1 ER -