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PDBsum entry 1mst
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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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Crystal structures of ms2 capsids with mutations in the subunit fg loop.
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Authors
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N.J.Stonehouse,
K.Valegård,
R.Golmohammadi,
S.Van den worm,
C.Walton,
P.G.Stockley,
L.Liljas.
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Ref.
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J Mol Biol, 1996,
256,
330-339.
[DOI no: ]
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
95%.
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Abstract
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The loop between the F and G beta strands (FG loop) of the bacteriophage MS2
coat protein subunit forms inter-subunit contacts around the 5-fold and 3-fold
(quasi 6-fold) axes of the T=3 protein shell. In capsids, the loop is found in
two very different conformations, one in B subunits, which form the 5-fold
contact, and one in A and C subunits, which form the quasi 6-fold contact. One
proline residue, Pro78, is strictly conserved in the coat protein of all related
bacteriophages, and in the case of MS2 this proline residue is preceded by a cis
peptide bond in the B subunit. In order to probe the role of the FG loop in
capsid assembly, we have determined the crystal structures of two MS2 capsids,
formed by coat proteins with mutations at two positions in the FG loop, P78N or
E76D. These mutants show conformational changes in the FG loops that explain the
reduced temperature stability of the capsids. The P78N mutant has a normal trans
peptide bond at position 78.
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Figure 2.
Figure 2. Schematic drawing of six coat protein subunits. The three independent subunits A, B and C making up
one asymmetric unit of the icosahedron are drawn with black lines, and the three subunits A', B' and C' completing
the dimers are shown in grey. At the 3-fold and 5-fold axes, the FG loops of all interacting subunits are shown. The
position of the 3-fold and 5-fold axes are each shown with a stick. A drawing of an icosahedron in the same orientation
is shown (inset). The drawing was made using the program MOLSCRIPT (Kraulis, 1991).
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The above figure is
reprinted
by permission from Elsevier:
J Mol Biol
(1996,
256,
330-339)
copyright 1996.
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Secondary reference #1
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Title
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Structure determination of the bacteriophage ms2.
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Authors
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K.Valegård,
L.Liljas,
K.Fridborg,
T.Unge.
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Ref.
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Acta Crystallogr B, 1991,
47,
949-960.
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PubMed id
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Secondary reference #2
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Title
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The three-Dimensional structure of the bacterial virus ms2.
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Authors
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K.Valegård,
L.Liljas,
K.Fridborg,
T.Unge.
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Ref.
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Nature, 1990,
345,
36-41.
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PubMed id
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Secondary reference #3
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Title
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The structure of bacteriophage ms2
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Authors
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L.Liljas,
K.Valegard.
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Ref.
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semin virol, 1990,
1,
467.
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Secondary reference #4
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Title
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Purification, Crystallization and preliminary X-Ray data of the bacteriophage ms2.
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Authors
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K.Valegård,
T.Unge,
I.Montelius,
B.Strandberg,
W.Fiers.
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Ref.
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J Mol Biol, 1986,
190,
587-591.
[DOI no: ]
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PubMed id
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Figure 3.
Figure 3. Three crystal forms of the bacteriophage MS2. The cystals were produced by the vapour difFuion
echnique. (a) Type I crstals produced in hosphate buffer (pH 7.4) a 37°C; (b) type II crystals produced in Tris . HCl/
aline buffer (pH 7.4) at 19°C; (c) ype III crystals produced in phosphate buffer (pH 7.4) at 4°C. The bar represents
0.1 mm. For further crystallization details see Results.
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Figure 5.
Figure 5. X-ray diffraction pattern of an MS2 crystal of type I. The X-ray photograph wa obtained by the use of an
Elliott rotating-anode X-ry generator, operated at 35 k and 55 rnA> and an Eraf-Nonius Arndt-Wonaeott camera.
he X-ray beam was filtered a,nd focused with nickel mirrors (Harrion, 1968). The crytal O,35 mm x 0.35 mm x
.15 mm, was oscillated 0.5'' around the a*-axis and the time of exposure was 20 h. The film-to-crystal distance was
90 mm giving a resolution limit of 2.6 A at the edge of the photograph.
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The above figures are
reproduced from the cited reference
with permission from Elsevier
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