Visualization of alpha-helical features in a density map constructed using 9 molecular images of the 1.8 MDa icosahedral core of pyruvate dehydrogenase.

Journal Article (Journal Article)

Strategies to achieve the highest resolutions in structures of protein complexes determined by cryo-electron microscopy generally involve averaging information from large numbers of individual molecular images. However, significant limitations are posed by heterogeneity in image quality and in protein conformation that are inherent to large data sets of images. Here, we demonstrate that the combination of iterative refinement and stringent molecular sorting is an effective method to obtain substantial improvements in map quality of the 1.8 MDa icosahedral catalytic core of the pyruvate dehydrogenase complex from Bacillus stearothermophilus. From a starting set of 42,945 images of the core complex, we show that using only the best 139 particles in the data set produces a map that is superior to those constructed with greater numbers of images, and that the location of many of the alpha-helices in the structure can be unambiguously visualized in a map constructed from as few as 9 particles.

Full Text

Duke Authors

Cited Authors

  • Borgnia, MJ; Shi, D; Zhang, P; Milne, JLS

Published Date

  • August 2004

Published In

Volume / Issue

  • 147 / 2

Start / End Page

  • 136 - 145

PubMed ID

  • 15193642

International Standard Serial Number (ISSN)

  • 1047-8477

Digital Object Identifier (DOI)

  • 10.1016/j.jsb.2004.02.007


  • eng

Conference Location

  • United States