State-of-the-Art Three-Dimensional Chemical Characterization of Solid Oxide Fuel Cell Using Focused Ion Beam Time-of-Flight Secondary Ion Mass Spectrometry Tomography.

In this paper the potential of time-of-flight secondary ion mass spectroscopy combined with focused ion beam technology to characterize the composition of a solid oxide fuel cell (SOFC) in three-dimension is demonstrated. The very high sensitivity of this method allows even very small amounts of elements/compounds to be detected and localized. Therefore, interlayer diffusion of elements between porous electrodes and presence of pollutants can be analyzed with a spatial resolution of the order of 100 nm.

Location of the dsRNA-dependent polymerase, VP1, in rotavirus particles.

Double-stranded RNA (dsRNA) viruses transcribe and replicate RNA within an assembled, inner capsid particle; only plus-sense mRNA emerges into the intracellular milieu. During infectious entry of a rotavirus particle, the outer layer of its three-layer structure dissociates, delivering the inner double-layered particle (DLP) into the cytosol. DLP structures determined by X-ray crystallography and electron cryomicroscopy (cryoEM) show that the RNA coils uniformly into the particle interior, avoiding a "fivefold hub" of more structured density projecting inward from the VP2 shell of the DLP along each of the twelve 5-fold axes.

Architecture of a dodecameric bacterial replicative helicase.

Hexameric DnaB helicases are often loaded at DNA replication forks by interacting with the initiator protein DnaA and/or a helicase loader (DnaC in Escherichia coli). These loaders are not universally required, and DnaB from Helicobacter pylori was found to bypass DnaC when expressed in E. coli cells.

Structure of RavA MoxR AAA+ protein reveals the design principles of a molecular cage modulating the inducible lysine decarboxylase activity.

The MoxR family of AAA+ ATPases is widespread throughout bacteria and archaea but remains poorly characterized. We recently found that the Escherichia coli MoxR protein, RavA (Regulatory ATPase variant A), tightly interacts with the inducible lysine decarboxylase, LdcI/CadA, to form a unique cage-like structure. Here, we present the X-ray structure of RavA and show that the αβα and all-α subdomains in the RavA AAA+ module are arranged as in magnesium chelatases rather than as in classical AAA+ proteins.

Nucleoprotein-RNA orientation in the measles virus nucleocapsid by three-dimensional electron microscopy.

Recombinant measles virus nucleoprotein-RNA (N-RNA) helices were analyzed by negative-stain electron microscopy. Three-dimensional reconstructions of trypsin-digested and intact nucleocapsids coupled to the docking of the atomic structure of the respiratory syncytial virus (RSV) N-RNA subunit into the electron microscopy density map support a model that places the RNA at the exterior of the helix and the disordered C-terminal domain toward the helix interior, and they suggest the position of the six nucleotides with respect to the measles N protomer.