Cryoelectron microscopic structure

Transmission electron microscopy (TEM) can resolve features down to about 1 nm and allows the use of electron diffraction to characterize the structure. Since electrons must pass through the sample however, the technique is limited to thin films. One cryoelectron microscopic study of fatty-acid Langmuir films on vitrified water [13] showed faceted crystals. The application of TEM to Langmuir-Blodgett films is discussed in Chapter XV. 

Rossmann suggested that the canyons form the binding site for the rhi-novirus receptor on the surface of the host cells. The receptor for the major group of rhinoviruses is an adhesion protein known as lCAM-1. Cryoelectron microscopic studies have since shown that ICAM-1 indeed binds at the canyon site. Such electron micrographs of single virus particles have a low resolution and details are not visible. However, it is possible to model components, whose structure is known to high resolution, into the electron microscope pictures and in this way obtain rather detailed information, an approach pioneered in studies of muscle proteins as described in Chapter 14. 

Dube P, Bacher G, Stark H, Mueller F, Zemlin F, van Heel M, Brimacombe R (1998) Correlation of the expansion segments in mammalian rRNA with the fine structure of the 80 S ribosome a cryoelectron microscopic reconstruction of the rabbit reticulocyte ribosome at 21 A resolution. J Mol Biol 279 403-421... 

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