Differentiation of CC vs CXC Chemokine Dimers with GAG Octasaccharide Binding Partners: An Ion Mobility Mass Spectrometry Approach

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• 作者：Youjin Seo ; Armann Andaya ; Christian Bleiholder ; Julie A. Leary
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：March 20, 2013
• 年：2013
• 卷：135
• 期：11
• 页码：4325-4332
• 全文大小：446K
• 年卷期：v.135,no.11(March 20, 2013)
• ISSN：1520-5126

文摘

Chemokines, 8 kDa proteins implicated in leukocyte migration via oligomerization, bind to glycosaminoglycans (GAGs) during the inflammation response as a means to regulate chemokine migration. Structural characterization of chemokines non-covalently bound to GAGs provides physiologically meaningful data in regard to routine inmmunosurveillance and disease response. In order to analyze the structures resulting from the GAG:chemokine interaction, we employed ion mobility mass spectrometry (IMMS) to analyze monocyte chemoattractant protein-1 (MCP-1), a CC chemokine, and interleukin-8 (IL-8), a CXC chemokine, along with their individual interactions with GAG heparin octasaccharides. We show that MCP-1 and IL-8 are physiologically present as a dimer, with MCP-1 having two variants of its dimeric form and IL-8 having only one. We also show that the MCP-1 dimer adopts two conformations, one extended and one compact, when bound to a dodecasulfated heparin octasaccharide. Binding of MCP-1 to heparin octasaccharide isomers of varying sulfation patterns results in similar arrival time distribution values, which suggests minimal distinguishing features among the resultant complexes. Additionally, tandem mass spectrometry (MS/MS) showed that the binding of MCP-1 to a heparin octasaccharide has different dissociation patterns when compared with the corresponding IL-8 bound dimer. Overall, IMMS and MS/MS were used to better define the structural tendencies and differences associated with CC and CXC dimers when associated with GAG octasaccharides.