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Title
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Preliminary crystallographic studies of bacteriophage T4 fibritin confirm a trimeric coiled-coil structure.
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Authors
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S.V.Strelkov,
Y.Tao,
M.G.Rossmann,
L.P.Kurochkina,
M.M.Shneider,
V.V.Mesyanzhinov.
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Ref.
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Virology, 1996,
219,
190-194.
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PubMed id
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Abstract
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Fibritin, a 52-kDa product of gene wac of bacteriophage T4, forms fibrous
"whiskers" that connect to the phage tail and facilitate the later stages of
phage assembly. Preliminary experiments suggest that fibritin is a trimer, and
its predominant central part has a parallel alpha-helical coiled-coil structure.
To investigate the oligomerization and function of fibritin, we have designed
and studied two related deletion mutants, denoted M and E, that consist of its
last 75 and 120 amino acids, respectively. Both proteins contain part of the
coiled-coil region and the 29 amino acid carboxy-terminal domain essential for
the trimerization of fibritin. The proteins are expressed as a soluble product
in an Escherichia coli system. We have obtained crystals of fibritins M and E.
Complete native X-ray diffraction data sets have been collected to 1.85 and 2.7
A resolution, respectively. The crystals have space group P3 with a=44.3 A,
c=91.3 A (fibritin M) and R32 with a=41.2 A, b=358.7 A (fibritin E) in the
hexagonal setting. Symmetry and packing considerations show that fibritin is a
triple coiled coil.
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