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PDBsum entry 2mbo
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Signaling protein
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PDB id
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2mbo
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References listed in PDB file
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Key reference
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Title
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Unique structural, Dynamical, And functional properties of k11-Linked polyubiquitin chains.
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Authors
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C.A.Castañeda,
T.R.Kashyap,
M.A.Nakasone,
S.Krueger,
D.Fushman.
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Ref.
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Structure, 2013,
21,
1168-1181.
[DOI no: ]
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PubMed id
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Abstract
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K11-linked polyubiquitin chains play important signaling and regulatory roles in
both degradative and nonproteolytic pathways in eukaryotes. To understand the
structural basis of how these chains are recognized and distinguished from other
polyubiquitins, we determined solution structures of K11-linked diubiquitin
(K11-Ub2) in the absence and presence of salt. These structures reveal that
K11-Ub2 adopts conformations distinct from those of K48-linked or K63-linked
chains. Importantly, our solution NMR and SANS data are inconsistent with
published crystal structures of K11-Ub2. We found that increasing salt
concentration compacts K11-Ub2 and strengthens interactions between the two Ub
units. Binding studies indicate that K11-Ub2 interacts with ubiquitin-receptor
proteins from both proteasomal and nonproteasomal pathways but with intermediate
affinity and different binding modes than either K48-linked or K63-linked
diubiquitin. Our data support the hypothesis that polyubiquitin chains of
different linkages possess unique conformational and dynamical properties,
allowing them to be recognized differently by downstream receptor proteins.
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