Each
of
the
20
hexameres
has
6
neighbours
(hexagonal
packing).
The
RNA
is
present
in
the
form
of
a,
single
chain
which
forms
a
series
of
loops
projecting
into
the
protein
clusters.
Cucumber
mosaic
virus
(CMV)
Icosahedral
T=3
class.
Particle
weight
5.5x1O6.
Contains
18%
RNA
of
4
classes:
1.0-1.3,
0.9-1.1,
0.7-0.8
and
O.3x
106
daltons.
The
three
largest
are
required
for
infectivity.
The
virion
has
180
molecules
of
coat
protein
(MW
25,000).
