Selective Disulfide Bond Cleavage in Gold(I) Cationized Polypeptide Ions Formed via Gas-Phase Ion/Ion Cation Switching

详细信息    查看全文

• 作者：Harsha P. Gunawardena ; Richard A. J. O'Hair ; Scott A. McLuckey
• 刊名：Journal of Proteome Research
• 出版年：2006
• 出版时间：September 2006
• 年：2006
• 卷：5
• 期：9
• 页码：2087 - 2092
• 全文大小：142K
• 年卷期：v.5,no.9(September 2006)
• ISSN：1535-3907

文摘

Gaseous multiply protonated disulfide-linked peptides have been subjected to reactions with AuCl₂^- ionsto explore the possibility of effecting cation switching ofAu⁺ for two protons and to determine whether cationization by Au⁺ ions affords selective dissociation of disulfidelinkages. The incorporation of Au⁺ into several modeldisulfide-linked peptides proved to be straightforward.The primary ion/ion reaction channels were proton transfer, which does not lead to Au⁺ incorporation, andattachment of AuCl₂^- ions to the polypeptide cation, whichdoes incorporate Au⁺. Fragmentation of the attachmentproduct, the extent of which varied with peptide andcharge state, led to losses of one or more molecules ofHCl and, to some extent, cleavage of polypeptides at thedisulfide linkage into its two constituent chains. Collisionalactivation of the intact metal-ion-incorporated peptidesshowed cleavage of the disulfide linkage to be a major,and in some cases exclusive, process. Cations withprotons as the only cationizing agents showed only smallcontributions from cleavage of the disulfide linkage. Theseresults indicate that Au⁺ incorporation into a disulfide-linked polypeptide ion is a promising way to effectselective dissocation of disulfide bonds. Cation switchingvia ion/ion reactions is a convenient means for incorporating gold and is attractive because it avoids the requirement of adding metal salts to the analyte solution.