Biology Reference
In-Depth Information
..
Turnip Yellow Mosaic Virus
: A Plant Virus
TYMV is from the family
. The virus can be found in Europe. The
host range is confined to plants from the family
Tymoviridae
also known as the
mustard or cabbage family. Chinese cabbage is used for propagation. TYMV
virions have icosahedral
Cruciferae
= 3 symmetry; they consist of 180 identical coat
protein units, and are about 28 nm in diameter. The genome is positive-sense,
single-stranded RNA (from DPV; http://www.dpvweb.net).
T
..
Flock House Virus
: An Insect Virus
FHV is a member of the
family. It infects insects, specifically the
New Zealand grass grub. The virus was named after a former agricultural
research station (Flock House) on the north island of New Zealand, where
scientists discovered that FHV was responsible for dead grass grubs.
FHV particles consists of 180 identical coat proteins arranged in a
Nodaviridae
T =
3 symmetry lattice; the structure has been solved by X-ray crystallography
(Fisher
., 1993). The genome is a bipartite, positive-sense, single-stranded
RNA genome (Krishna & Schneemann, 1999).
FHV particles can be produced in
et al
cells with yields of 1 mg/5-10
mL cell culture (Schneemann & Marshall, 1998). VLPs or mutant particles can
be expressed in a heterologous system based on baculovirus (Schneemann
Drosophila
et
al
assembly methods
are discussed in Chapter 3.) The heterologous expression combined with the
capsid structure has allowed the display of relatively large protein domains
on the capsid surface. FHV is relatively new to the field of nanotechnology, and
because of its unique facility in protein display, it has primarily been exploited
for vaccine development strategies (Manayani
., 1993). (Heterologous expression systems and
in vitro
et al
., 2007) (see Chapter 8).
.. hK: A Bacteriophage
HK97 is an
. The phages consist of a
head and a tail, are not enveloped, and encapsidate a linear double-stranded
DNA genome. The head is the structure of interest for nanotechnology. The
phage head has icosahedral
Enterobacteria
phage that infects
E
.
coli
= 7 symmetry and a diameter of 66 nm.
The most intriguing feature of the virions is their maturation process,
during which the particles undergo expansion from 54 nm (prohead II) to
66 nm (head II) (Fig. 2.11) (Gertsman
T
., 2008). VNPs in
general can be regarded as rigid and robust structures; however, one has to
keep in mind that they are also highly dynamic structures. For example, we
already mentioned the pH- and metal ion-dependent swelling mechanism of
CCMV (see Section 2.2.2). HK97 particles undergo an expansion and increase
et al
., 2009; Lee
et al
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