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PDBsum entry 1s2e
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Viral protein
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PDB id
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1s2e
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Contents |
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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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The structure of bacteriophage t4 gene product 9: the trigger for tail contraction.
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Authors
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V.A.Kostyuchenko,
G.A.Navruzbekov,
L.P.Kurochkina,
S.V.Strelkov,
V.V.Mesyanzhinov,
M.G.Rossmann.
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Ref.
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Structure, 1999,
7,
1213-1222.
[DOI no: ]
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PubMed id
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Abstract
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BACKGROUND: The T4 bacteriophage consists of a head, filled with double-stranded
DNA, and a complex contractile tail required for the ejection of the viral
genome into the Escherichia coli host. The tail has a baseplate to whïch are
attached six long and six short tail fibers. These fibers are the sensing
devices for recognizing the host. When activated by attachment to cell
receptors, the fibers cause a conformational transition in the baseplate and
subsequently in the tail sheath, which initiates DNA ejection. The baseplate is
a multisubunit complex of proteins encoded by 15 genes. Gene product 9 (gp9) is
the protein that connects the long tail fibers to the baseplate and triggers the
tail contraction after virus attachment to a host cell. RESULTS: The crystal
structure of recombinant gp9, determined to 2.3 A resolution, shows that the
protein of 288 amino acid residues assembles as a homotrimer. The monomer
consists of three domains: the N-terminal domain generates a triple coiled coil;
the middle domain is a mixed, seven-stranded beta sandwich with a topology not
previously observed; and the C-terminal domain is an eight-stranded,
antiparallel beta sandwich having some resemblance to 'jelly-roll' viral capsid
protein structures. CONCLUSIONS: The biologically active form of gp9 is a
trimer. The protein contains flexible interdomain hinges, which are presumably
required to facilitate signal transmission between the long tail fibers and the
baseplate. Structural and genetic analyses show that the C-terminal domain is
bound to the baseplate, and the N-terminal coiled-coil domain is associated with
the long tail fibers.
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Figure 4.
Figure 4. Topology diagrams for (a) the middle domain and
(b) the C-terminal domain. (c) Topology of a jelly-roll fold, as
occurs in many viral capsid proteins. (d) The b-annulus
connecting the middle and C-terminal domains. The amino acids
and hydrogen bonding between subunits A, B and C are shown.
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The above figure is
reprinted
by permission from Cell Press:
Structure
(1999,
7,
1213-1222)
copyright 1999.
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