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PDBsum entry 1a6c
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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 tobacco ringspot virus: a link in the evolution of icosahedral capsids in the picornavirus superfamily.
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Authors
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V.Chandrasekar,
J.E.Johnson.
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Ref.
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Structure, 1998,
6,
157-171.
[DOI no: ]
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PubMed id
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Abstract
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BACKGROUND: Tobacco ringspot virus (TRSV) is a member of the nepovirus genus of
icosahedral RNA plant viruses that cause disease in fruit crops. Nepoviruses,
comoviruses and picornaviruses are classified in the picornavirus superfamily.
Crystal structures of comoviruses and picornaviruses and the molecular mass of
the TRSV subunit (sufficient to accommodate three beta-barrel domains) suggested
that nepoviruses may represent a link in the evolution of the picornavirus
capsids from a T = 3 icosahedral virus. This evolutionary process is thought to
involve triplication of the capsid protein gene, to encode a three-domain
polyprotein, followed by development of cleavage sites in the interdomain
linking regions. Structural studies on TRSV were initiated to determine if the
TRSV subunit corresponds to the proposed uncleaved three-domain polyprotein.
RESULTS: The 3.5 A resolution structure of TRSV shows that the capsid protein
consists of three beta-barrel domains covalently linked by extended
polypeptides. The order of connectivity of the domains in TRSV confirms the
proposed connectivity for the precleaved comovirus and picornavirus capsid
polyprotein. Structural differences between equivalent domains in TRSV and
comoviruses are confined to the external surface loops, interdomain connecting
polypeptides and N termini. The three different domains within TRSV and
comoviruses are more closely related at the structural level than the three
individual domains within picornaviruses. CONCLUSIONS: The structural results
confirm the notion of divergent evolution of the capsid polyproteins of
nepoviruses, comoviruses and picornaviruses from a common ancestor. A number of
residues were found to be conserved among various nepoviruses, some of which
stabilize the quaternary structure of the three domains in the TRSV capsid
protein subunit. Two conserved regions were identified on the external surface
of TRSV, however, mutational studies will be needed to understand their
functional significance. Nepoviruses transmitted by the same nematode species do
not share regions with similar amino acid composition on the viral surface.
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Figure 4.
Figure 4. Interdomain linking polypeptides in TRSV, (a)
Stereo view of the Ca trace (white) of the capsid protein from
inside the capsid with the electron density for the two
domain-linking polypeptides. The pink density shows the link
between the C and B domains and the brown density shows the link
between the B and A domains. (b) An enlarged view of (a) showing
the difference in the conformation of the C-B domain-connecting
polypeptides in TRSV (yellow) and BPMV (green).
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The above figure is
reprinted
by permission from Cell Press:
Structure
(1998,
6,
157-171)
copyright 1998.
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Secondary reference #1
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Title
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Expression of tobacco ringspot virus capsid protein and satellite RNA in insect cells and three-Dimensional structure of tobacco ringspot virus-Like particles.
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Authors
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S.Singh,
R.Rothnagel,
B.V.Prasad,
B.Buckley.
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Ref.
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Virology, 1995,
213,
472-481.
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PubMed id
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Secondary reference #2
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Title
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Corrigendum to "nucleotide sequence and in vitro expression of the capsid protein gene of tobacco ringspot virus" [virus research 30 (1993) 335-349].
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Authors
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B.Buckley,
S.Silva,
S.Singh.
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Ref.
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Virus Res, 1995,
35,
111.
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PubMed id
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Secondary reference #3
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Title
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Nucleotide sequence and in vitro expression of the capsid protein gene of tobacco ringspot virus.
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Authors
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B.Buckley,
S.Silva,
S.Singh.
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Ref.
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Virus Res, 1993,
30,
335-349.
[DOI no: ]
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PubMed id
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Secondary reference #4
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Title
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Protein-Rna interactions in an icosahedral virus at 3.0 a resolution.
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Authors
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Z.G.Chen,
C.Stauffacher,
Y.Li,
T.Schmidt,
W.Bomu,
G.Kamer,
M.Shanks,
G.Lomonossoff,
J.E.Johnson.
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Ref.
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Science, 1989,
245,
154-159.
[DOI no: ]
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PubMed id
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Secondary reference #5
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Title
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Structure of a human common cold virus and functional relationship to other picornaviruses.
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Authors
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M.G.Rossmann,
E.Arnold,
J.W.Erickson,
E.A.Frankenberger,
J.P.Griffith,
H.J.Hecht,
J.E.Johnson,
G.Kamer,
M.Luo,
A.G.Mosser.
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Ref.
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Nature, 1985,
317,
145-153.
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PubMed id
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