Source:http://linkedlifedata.com/resource/pubmed/id/12235153
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:dateCreated |
2002-11-26
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| pubmed:abstractText |
The homodimeric form of a recombinant cytokine interleukin-6 (IL-6(D)) is known to antagonize IL-6 signaling. In this study, spatially proximal residues between IL-6 chains in IL-6(D) were identified using a method for specific recognition of intermolecular cross-linked peptides. Our strategy involved mixing 1:1 (15)N-labeled and unlabeled ((14)N) protein to form a mixture of isotopically labeled and unlabeled homodimers, which was chemically cross-linked. This cross-linked IL-6(D) was subjected to proteolysis by trypsin and the generated peptides were analyzed by electrospray ionization time-of-flight mass spectrometry (MS). Molecular ions from cross-linked peptides of intermolecular origin are labeled with [(15)N/(15)N] + [(15)N/(14)N] + [(14)N/(15)N] + [(14)N/(14)N] yielding readily identified triplet/quadruplet MS peaks. All other peptide species are labeled with [(15)N] + [(14)N] yielding doublet peaks. Intermolecular cross-linked peptides were identified by MS, and cross-linked residues were identified. This intermolecular cross-link detection method, which we have designated "mixed isotope cross-linking" MIX may have more general application to protein-protein interaction studies. The pattern of proximal residues found was consistent with IL-6(D) having a domain-swapped fold similar to IL-10 and interferon-gamma. This fold implies that IL-6(D)-mediated antagonism of IL-6 signaling is caused by obstruction of cooperative gp130 binding on IL-6(D), rather than direct blocking of gp-130-binding sites on IL-6(D).
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| pubmed:language |
eng
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| pubmed:citationSubset |
IM
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| pubmed:chemical | |
| pubmed:status |
MEDLINE
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| pubmed:author | |
| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
46487-92
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| pubmed:dateRevised |
2004-11-17
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| pubmed:articleTitle |
Characterization of an antagonist interleukin-6 dimer by stable isotope labeling, cross-linking, and mass spectrometry.
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| pubmed:affiliation |
Joint ProteomicS Laboratory, The Ludwig Institute for Cancer Research and The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3050, Australia.
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