Single
Stranded
DNA
-
ssDNa
It
may
be
linear
(e.
g.
parvoiruses)
or
circular
(e-
g. φXI74,
fd
and
M13).
First discovered is φX174 by Sinsheimer and his associates in the late 1950s, it differs from double stranded DNA in the following respects:
(1)
Ultra
violet
absorption
of
dsDNA
remains
constant
from
0
to
80°C,
and
then
rises
rapidly
(80°C
is
the
critical
melting
point).
ssDNA
shows
a
steady
increase
in
UV
absorption
from
20°C
to
90°C.
(2) dsDNA is resistant to the action of formaldehyde. In ssDNA the reactive sites are exposed, and, therefore it is not resistant to formaldehyde.
Index >> Virus Structure and Classification >> Single Stranded DNA (ssDNA)
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