Single-particle cryogenic electron microscopy (cryo-EM) can now yield near-atomic resolution structures of biological complexes. However, the reference-based alignment algorithms commonly used in cryo-EM suffer from reference bias, limiting their applicability (also known as the 'Einstein from random noise' problem). Low-dose cryo-EM therefore requires robust and objective approaches to reveal ...

Structural analysis of biological membranes is important for understanding cell and sub-cellular organelle function as well as their interaction with the surrounding environment. Imaging of whole cells in three dimension at high spatial resolution remains a significant challenge, particularly for thick cells. Cryo-transmission soft X-ray microscopy (cryo-TXM) has recently gained popularity to i...

Single-particle cryo-EM is a powerful approach to determine the structure of large macromolecules and assemblies thereof in many cases at subnanometer resolution. It has become popular to refine or flexibly fit atomic models into density maps derived from cryo-EM experiments. These density maps are typically significantly lower in resolution than electron density maps obtained from X-ray diffra...

Cryo-electron tomography is an important research method to study the cell ultrastructure in a near native state, especially in the structural biology and cell biological fields[1]. There are a few cellular specimens that bacterial and eukaryotic cells can be examined directly by cryo-TEM [2, 3], but eukaryotic and tissue are difficult to realize for the specimen thickness. The primary method t...

High-efficiency disruption of bacteria can be accomplished in 2 or more min by the new procedure of liquid nitrogen cryo-impacting. Release of the dipicolinic acid-Ca2+ chelate paralleled the breakage of Bacillus megaterium endospores. Lactate dehydrogenase activity was much better in supernates from liquid nitrogen cryo-impacting-broken Escherichia coli cells than in those from sonically treat...

In this issue, Kuhn et al. (2007) report the complete structure of the 14-subunit yeast RNA polymerase (Pol) I enzyme at 12 A resolution using cryo-electron microscopy (cryo-EM). Their study reveals that three subunits of Pol I perform functions in transcription elongation that are outsourced to the transcription factors TFIIF and TFIIS in the analogous Pol II transcription system.

Abstract When biological samples are first exposed to electrons in cryo-electron microcopy (cryo-EM), proteins exhibit a rapid ‘burst’ phase of beam-induced motion that cannot be corrected with software. This lowers the quality initial frames, which least damaged by electrons. Hence, they commonly excluded or down-weighted during data processing, reducing undamaged signal and resolution reconst...

BACKGROUND Recent advances in nanoparticle design have generated new possibilities for nano-biotechnology and nano-medicine. Here we used cryo-soft X-ray tomography (cryo-SXT) to collect comprehensive three-dimensional (3D) data to characterise the interaction of superparamagnetic iron oxide nanoparticles (SPION) with a breast cancer cell line. RESULTS We incubated MCF-7 (a human breast cance...

Cryo-electron tomography (cryo-ET) can be used to reconstruct three-dimensional (3D) volumes, or tomograms, from a series of tilted two-dimensional images biological objects in their near-native states situ vitro. 3D subvolumes, subtomograms, containing particles interest extracted aligned, and averaged process called subtomogram averaging (STA). STA overcomes the low signal noise ratio within ...

Single particle electron cryomicroscopy (cryo-EM) allows for structures of proteins and protein complexes to be determined from images of non-crystalline specimens. Cryo-EM data analysis requires electron microscope images of randomly oriented ice-embedded protein particles to be rotated and translated to allow for coherent averaging when calculating three-dimensional (3D) structures. Rotation ...