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PDBsum entry 1ej6
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Contents |
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1284 a.a.
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1031 a.a.
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1221 a.a.
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417 a.a.
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Structure of the reovirus core at 3.6 a resolution.
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Authors
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K.M.Reinisch,
M.L.Nibert,
S.C.Harrison.
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Ref.
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Nature, 2000,
404,
960-967.
[DOI no: ]
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PubMed id
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Abstract
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The reovirus core is an assembly with a relative molecular mass of 52 million
that synthesizes, modifies and exports viral messenger RNA. Analysis of its
structure by X-ray crystallography shows that there are alternative, specific
and completely non-equivalent contacts made by several surfaces of two of its
proteins; that the RNA capping and export apparatus is a hollow cylinder, which
probably sequesters its substrate to ensure completion of the capping reactions;
that the genomic double-stranded RNA is coiled into concentric layers within the
particle; and that there is a protein shell that appears to be common to all
groups of double-stranded RNA viruses.
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Figure 1.
Figure 1: The reovirus core particle, represented by C
alpha- traces
of the constituent subunits. lambda- 1
(relative molecular mass (M[r]) 142K (ref.46), 120 copies; shown
in red) forms the shell that packages RNA and defines the
symmetry and size of the particle.  2
(M[r] 47K, 150 copies; shown as yellow, green and white nodules)
stabilizes the  1
shell. 2
(M[ r] 144K, 60 copies; shown in blue) forms turret-like
structures around the fivefold axes that cap the nascent mRNA
and organize its extrusion.
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Figure 6.
Figure 6: The capping complex. a, b, 2
turret (about 120 Å diameter and 80 Å tall) viewed from the top
and side, respectively. The five elongated 2
monomers, each shown in a different colour, wrap around the
outer surface, with their long axes at about 45° to the radial
direction. c, The 2
monomer, viewed from the inside of the pentamer (the blue
monomer in b). The GTase domain is red, methylase-1 is yellow,
methylase-2 is green and the immunoglobulin-like domains are
blue. Red SAH molecules mark the SAM-binding sites. d, GTase
domain at 90° to c, in graded colours with the N terminus red
and the C terminus blue. Side chains of K190 and K171 are shown.
e, Diagrams of SAM-binding domains. The 'universal' SAM-binding
domain is shown in black19, 20; methylase-1 is yellow and
methylase-2 is green. Secondary structural elements are aligned
vertically with their equivalents in the universal fold. The
SAM-binding position with respect to the  -sheet
is labelled. f, Two monomers of 2
(labelled A and B) with the immunoglobulin-like domains detached
and viewed from the interior of the turret. Monomer A includes
GTase 'a' and methylases 'a1' and 'a2'; B includes 'b', 'b1' and
'b2'. Coloured as in c. Red SAH molecules indicate SAM-binding
locations. Blue arrows indicate the GTase active site. g, SAH
density for methylase-1 in a 4 Å, 2F[o]- F[c] map made with data
from crystals soaked in 2 mM SAH. SAH binding is accompanied by
conformational changes in residues 519-524 and 579-587. Some
residues that may interact with SAH are labelled. h, SAH density
for methylase-2.
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
Nature
(2000,
404,
960-967)
copyright 2000.
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