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PDBsum entry 4jce
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Viral protein
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PDB id
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4jce
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DOI no:
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Mbio
4:e00247
(2013)
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PubMed id:
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Progressive multifocal leukoencephalopathy-associated mutations in the JC polyomavirus capsid disrupt lactoseries tetrasaccharide c binding.
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M.S.Maginnis,
L.J.Ströh,
G.V.Gee,
B.A.O'Hara,
A.Derdowski,
T.Stehle,
W.J.Atwood.
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ABSTRACT
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The human JC polyomavirus (JCPyV) is the causative agent of the fatal,
demyelinating disease progressive multifocal leukoencephalopathy (PML). The
Mad-1 prototype strain of JCPyV uses the glycan lactoseries tetrasaccharide c
(LSTc) and serotonin receptor 5-HT2A to attach to and enter into host cells,
respectively. Specific residues in the viral capsid protein VP1 are responsible
for direct interactions with the α2,6-linked sialic acid of LSTc. Viral
isolates from individuals with PML often contain mutations in the sialic
acid-binding pocket of VP1 that are hypothesized to arise from positive
selection. We reconstituted these mutations in the Mad-1 strain of JCPyV and
found that they were not capable of growth. The mutations were then introduced
into recombinant VP1 and reconstituted as pentamers in order to conduct binding
studies and structural analyses. VP1 pentamers carrying PML-associated mutations
were not capable of binding to permissive cells. High-resolution structure
determination revealed that these pentamers are well folded but no longer bind
to LSTc due to steric clashes in the sialic acid-binding site. Reconstitution of
the mutations into JCPyV pseudoviruses allowed us to directly quantify the
infectivity of the mutants in several cell lines. The JCPyV pseudoviruses with
PML-associated mutations were not infectious, nor were they able to engage
sialic acid as measured by hemagglutination of human red blood cells. These
results demonstrate that viruses from PML patients with single point mutations
in VP1 disrupt binding to sialic acid motifs and render these viruses
noninfectious. IMPORTANCE Infection with human JC polyomavirus (JCPyV) is common
and asymptomatic in healthy individuals, but during immunosuppression, JCPyV can
spread from the kidney to the central nervous system (CNS) and cause a fatal,
demyelinating disease, progressive multifocal leukoencephalopathy (PML).
Individuals infected with HIV, those who have AIDS, or those receiving
immunomodulatory therapies for autoimmune diseases are at serious risk for PML.
Recent reports have demonstrated that viral isolates from PML patients often
have distinct changes within the major capsid protein. Our structural-functional
approach highlights that these mutations result in abolished engagement of the
carbohydrate receptor motif LSTc that is necessary for infection. Viruses with
PML-associated mutations are not infectious in glial cells, suggesting that they
may play an alternative role in PML pathogenesis.
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');
}
}
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