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PDBsum entry 2og3
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Viral protein
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PDB id
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2og3
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References listed in PDB file
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Key reference
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Title
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Ribonucleocapsid formation of severe acute respiratory syndrome coronavirus through molecular action of the n-Terminal domain of n protein.
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Authors
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K.S.Saikatendu,
J.S.Joseph,
V.Subramanian,
B.W.Neuman,
M.J.Buchmeier,
R.C.Stevens,
P.Kuhn.
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Ref.
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J Virol, 2007,
81,
3913-3921.
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PubMed id
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Abstract
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Conserved among all coronaviruses are four structural proteins: the matrix (M),
small envelope (E), and spike (S) proteins that are embedded in the viral
membrane and the nucleocapsid phosphoprotein (N), which exists in a
ribonucleoprotein complex in the lumen. The N-terminal domain of coronaviral N
proteins (N-NTD) provides a scaffold for RNA binding, while the C-terminal
domain (N-CTD) mainly acts as oligomerization modules during assembly. The C
terminus of the N protein anchors it to the viral membrane by associating with M
protein. We characterized the structures of N-NTD from severe acute respiratory
syndrome coronavirus (SARS-CoV) in two crystal forms, at 1.17 A (monoclinic) and
at 1.85 A (cubic), respectively, resolved by molecular replacement using the
homologous avian infectious bronchitis virus (IBV) structure. Flexible loops in
the solution structure of SARS-CoV N-NTD are now shown to be well ordered around
the beta-sheet core. The functionally important positively charged beta-hairpin
protrudes out of the core, is oriented similarly to that in the IBV N-NTD, and
is involved in crystal packing in the monoclinic form. In the cubic form, the
monomers form trimeric units that stack in a helical array. Comparison of
crystal packing of SARS-CoV and IBV N-NTDs suggests a common mode of RNA
recognition, but they probably associate differently in vivo during the
formation of the ribonucleoprotein complex. Electrostatic potential distribution
on the surface of homology models of related coronaviral N-NTDs suggests that
they use different modes of both RNA recognition and oligomeric assembly,
perhaps explaining why their nucleocapsids have different morphologies.
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