Cryo-TEM image and 3D printed model of CNT and lipid layer to scale. Cryo-TEM image of a CNT porin. Inset, schematic showing CNT porin preparation and incorporation into liposomes; outlines of the bilayer (orange) and CNT (blue). Image was processed to enhance contrast. Nature 514, 612615.

S-layers are paracrystalline, two-dimensional protein lattices that cover the surfaces of many bacteria and archaea. Due to their biological significance and great potential as patterning elements in nanobiotechnology S-layer have been intensely investigated, yet their rules of assembly are not yet completely understood.

S-layer protein derived from Lysinibacillus sphaericus free in suspension. ACS Nano
Cryo-TEM image (2D projection) of an S-layer sheet laying on graphene and image cropping for 2D structural analysis. Yellow arrows point to protein adsorbed on the graphene surface, mostly oligomers in extended or partially folded conformations and probably monomers. The blue boxes a) and b) represent the image cropped sections and are shown in magnified views below the main panel. The three types of masks shown to the right of a) and b) were used, with the information let through shown in false blue. The rectangular mask, left row, was used for alignment by KerDenSOM, PCA, and ML. The results obtained using the circular mask letting only the boundary information, middle row, or using the circular mask letting only information from the tetrameric subunit adjacent to the boundary, right row, are essentially the same; we observe a discrete set of conformers and coupling between boundary and adjacent tetrameric units conformations. Scale bars: A) 50 nm; insets 10 nm. Angew. Chem. Int. Ed. Engl.

Many questions require direct imaging without averaging over ensembles or many realizations of a given molecule, as is typically done in Single Particle methods. Some examples are lipid bilayers, as in SUVs and similar model systems; self assembling systems lacking a quasi-crystalline order; Ribosomes interacting with flexible RNA stem-loops.

PopZ complexes. UA stained, pixel 3.5 Å. Cell
PopZ filaments in solution, observed in vitreous ice by cryo-TEM. Pixel 3.5 Å.
ParA-ATP Self-assembly in vitro. Nature Cell Biology
ParA-ATP Self-assembly in vitro.
RNA-DNA hybrids in solution, observed in vitreous ice by cryo-TEM. Inner diameter ~33 Å and outer diameter ~ 166 Å. Pixel 2.4 Å.
Cryo-TEM image of SUVs in solution, in the presence of Mg ions. The blue squares "A" and "B" enclose vesicles far and near the grid's carbon; the image is part of a series prepared to study the effect of ions and grid charging on sample preparation. Pixel 3.5 Å
Average of images from a CTF-corrected defocus series of SUVs obtained by cryo-TEM imaging. Three defocus values were average: 1.2 μm, 2.4 μm, and 3.6 μm. Pixel 3.5 Å.
Top right vesicle from previous defocus series averaged image.
Radial plot profile of the previous SUV.
C.c.CellPole.IM and OM lipid bilayers; S-layer. Image 450 nm by side, pixel 0.22 nm.
C.c.CellPole.IM and OM lipid bilayers; S-layer; chemotaxis apparatus. Image 450 nm by side, pixel 0.22 nm.
Ribosomes, RNA stem-loops stalling the ribosomes on mRNA, and mRNA-DNA hybrids in solution, observed in vitreous ice by cryo-TEM. Pixel 2.4 Å.
Ribosome and mRNA stem-loop, false colors.