Biology Reference
In-Depth Information
fluid under native conditions. Furthermore, environmental conditions
can be easily changed during the course of AFM experiments, allow-
ing study of the structural dynamics of viruses in response to envi-
ronmental and chemical stimuli.
In this chapter, we will demonstrate the capabilities of AFM in
probing the architecture of plant, animal and human viruses repre-
senting a wide size range (60 Å
m), imaged under a broad
range of conditions (air-dried, fully hydrated, various inorganic and
organic solutions) and constellations (single, in a crystal, dissected,
budding from cells).
−
0.5
µ
AFM Investigations of High-Resolution
Structures of Viruses
The overall morphology of viruses, having a wide range of geometri-
cal structures and spanning the size range from 16 nm for small T
1
icosahedral satellite viruses
6
to almost half a micron for poxviruses,
7
can be imaged by AFM under physiological conditions (Fig. 1).
Furthermore, AFM provides a resolution sufficient not only to visu-
alize the gross shape of virions, but also to unravel the molecular
details of their surfaces. Here, we will describe several applications of
AFM to probe high-resolution structures and assemblies of a wide
range of viruses.
=
Fig. 1.
(
a
) 16 nm diameter satellite tobacco mosaic virus (STMV) parti-
cles adsorbed on mica. (
b
) Brome mosaic virus (BMV) particles adsorbed on
mica. Capsomeres are evident on the virus surface. (
c
) Ty3 RT mutant virus-
like particles (VLPs). (
d
) Intracellular mature vaccinia (IMV) virus particles
adsorbed on mica.
