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PDBsum entry 3kqg
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Immune system
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PDB id
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3kqg
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References listed in PDB file
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Key reference
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Title
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Trimeric structure of langerin.
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Authors
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H.Feinberg,
A.S.Powlesland,
M.E.Taylor,
W.I.Weis.
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Ref.
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J Biol Chem, 2010,
285,
13285-13293.
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PubMed id
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Abstract
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Langerin, an endocytic receptor of Langerhans cells, binds pathogens such as
human immunodeficiency virus by recognition of surface glycoconjugates and
mediates their internalization into Birbeck granules. Langerin has an
extracellular region consisting of a C-type carbohydrate-recognition domain
(CRD) and a neck region that stabilizes formation of trimers. As in many other
C-type lectins, oligomerization is required for high affinity binding to glycan
ligands and is also likely to be important for determining specificity. To
facilitate structural analysis of the human langerin trimer, a truncated form of
the extracellular region, consisting of part of the neck and the CRD, has been
characterized. Like the full-length protein, truncated langerin exists as a
stable trimer in solution. Glycan array screening with the trimeric fragment
shows that high mannose oligosaccharides are the best ligands for langerin.
Structural analysis of the trimeric fragment of langerin confirms that the neck
region forms a coiled-coil of alpha-helices. Multiple interactions between the
neck region and the CRDs make the trimer a rigid unit with the three CRDs in
fixed positions and the primary sugar-binding sites separated by a distance of
42 A. The fixed orientation of the sugar-binding sites in the trimer is likely
to place constraints on the ligands that can be bound by langerin.
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