We present here the first
asymmetric, three-dimension
al reconstruction of
a t
ailed dsDNA virus, the m
ature b
acterioph
age
![]()
alt=""phi"" title=""phi"" border=""0"">29,
at subn
anometer resolution. This structure reve
als the rich det
ail of the
asymmetric inter
actions
and conform
ation
al dyn
amics of the
![]()
alt=""phi"" title=""phi"" border=""0"">29 protein
and DNA components,
and provides novel insight into the mech
anics of virus
assembly. For ex
ample, the dodec
americ he
ad-t
ail connector protein undergoes signific
ant re
arr
angement upon
assembly into the virion. Specific inter
actions occur between the tightly p
acked dsDNA
and the proteins of the he
ad
and t
ail. Of p
articul
ar interest
and novelty,
an
![]()
alt=""not, vert, simil
ar"" title=""not, vert, simil
ar"" border=""0"">60Å di
ameter toroid of dsDNA w
as observed in the connector-lower coll
ar c
avity. The extreme deform
ation th
at occurs over
a sm
all stretch of DNA is likely
a consequence of the high pressure of the p
ack
aged genome. This toroid structure m
ay help ret
ain the DNA inside the c
apsid prior to its injection into the b
acteri
al host.