Biology Reference
In-Depth Information
interactions between components of the trimers in the outer layer of
the capsid of viruses in
Reoviridae
stabilize the building blocks of the
second layer of the capsid. The increased height (as compared to the
inner layer) of these building blocks may be the result of the need for
these strong stabilizing interactions.
A virus with a big cavity inside a spherical shell can be generated
by a small variety of proteins — that is to say, in a genetically eco-
nomical manner — either by use of “flat” proteins, as described above
for P3 of RDV, or by construction of a capsid layer with a large
T-number. The disadvantage in the former case is the weakness of
inter-protein binding because of the limited area (margins) of the pro-
tein that is available for such binding; the disadvantage in the latter
case is the weakness of interactions because so many molecules bind to
one another. The weak interactions of the core capsid layer of RDV
seem to be reinforced by the well-fitting outer layer, composed of
the P8 protein. Conversely, the well-ordered outer layer seems to be
supported by the inner layer, which provides a scaffold to which the P8
T-trimers can bind tightly. Thus, the first-layer inner capsid and the
second-layer outer capsid proteins compensate for each other's respec-
tive weaknesses and form a rigid double-layered shell that creates a
cavity that is large enough for the genome and other essential proteins.
References
1.
Mertens PPC, Duncan R, Attoui H, Dermody TS. (2005) Family
Reoviridae
. In CM Fauquet, MA Mayao, J Maniloff,
et al
. (eds),
Virus
Taxonomy
. Elsevier Academic Press.
2.
Nakagawa A, Miyazaki N, Taka J,
et al
. (2003) Atomic structure of a
Rice dwarf virus reveals the self-assembly mechanism of the component
proteins.
Structure
11
: 1227-1238.
3.
Grimes JM, Burroughs JN, Gouet P,
et al
. (1998) The atomic structure
of the bluetongue virus core.
Nature
395
: 470-478.
4.
Reinisch KM, Nibert ML, Harrison SC. (2000) Structure of the
reovirus core at 3.6 Å resolution.
Nature
404
: 960-967.
5.
Naitow H, Morimoto Y, Mizuno H,
et al
. (1999) A low-resolution
structure of Rice dwarf virus determined by
ab initio
phasing.
Acta
Crystallogr D Biol Crystallogr
55
(Pt. 1): 77-84.
