Biology Reference
In-Depth Information
Fig. 10.
Proposed mechanism for the assembly of RDV.
2
On the basis of
the strengths of interactions among the various subunits, we propose the
following sequence of events.
(a)
Insertion of the amino-terminal arm of
P3B into P3A initiates the assembly of a P3 dimer. This P3A-P3B dimer acts
as the unit piece in the jigsaw puzzle.
(b)
Five dimers of P3 protein aggre-
gate around an icosahedral five-fold axis.
(c)
The pentameric aggregates of
P3 assemble to form the core structure of the RDV particle.
(d)
Trimers of
P8 act as unit pieces for the assembly of the outer layer and these trimers
attach to the icosahedral three-fold axis at the T-site first. Orientation of the
T-trimer of P8 proteins on the surface of the core at the icosahedral three-
fold axis is defined by electrostatic complementarity.
(e)
R-trimers of
the P8 protein then attach via interactions with the inner shell and with
the T-trimers.
(f )
Q-trimers and S-trimers attach to the core surface.
(g)
At the
final stage of viral assembly, P-trimers attach at the icosahedral five-fold axes
to generate the complete virus particle.
twist around each other, with tight binding at their intermolecular junc-
tions (Fig. 2). The binding energies are very high for all the reoviruses
for which such data are available: 175.6 kcal/mol for rotavirus;
169.6 kcal/mol for BTV; and 179.8 kcal/mol for RDV. The strong
