Selective disulfide bond cleavage in gold(I) cationized polypeptide ions formed via gas-phase ion/ion cation switching
Selective disulfide bond cleavage in gold(I) cationized polypeptide ions formed via gas-phase ion/ion cation switching
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DOI：
10.1021/pr0602794
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发表时间：
2006-09-01
影响因子：
4.4
通讯作者：
McLuckey, Scott A.
中科院分区：
文献类型：
--
作者：
Gunawardena, Harsha P.;O'Hair, Richard A. J.;McLuckey, Scott A.
气态多质子化的二硫键连接的肽已进行与AuCl 2-离子的反应，以探索影响阳离子开关的Au+为两个质子的可能性，并确定是否由Au+离子的阳离子化提供选择性解离的二硫键。将Au+掺入到几种模型二硫键连接的肽中被证明是简单的。主要的离子/离子反应通道是质子转移，这不会导致Au+的掺入，以及AuCl 2-离子与多肽阳离子的连接，这会掺入Au+。附着产物的片段化，其程度随肽和电荷状态而变化，导致一个或多个HCl分子的损失，并且在一定程度上导致多肽在二硫键处裂解成其两个组成链。完整的金属离子掺入肽的碰撞活化显示二硫键的裂解是一个主要的，在某些情况下是排他性的过程。带有质子的阳离子作为唯一的阳离子化剂，仅显示出二硫键断裂的微小贡献。这些结果表明，Au+掺入到二硫键连接的多肽离子是一种有前途的方式来实现选择性解离的二硫键。通过离子/离子反应的阳离子转换是用于掺入金的方便手段，并且是有吸引力的，因为它避免了向分析物溶液中添加金属盐的要求。
Gaseous multiply protonated disulfide-linked peptides have been subjected to reactions with AuCl2- ions to explore the possibility of effecting cation switching of Au+ for two protons and to determine whether cationization by Au+ ions affords selective dissociation of disulfide linkages. The incorporation of Au+ into several model disulfide-linked peptides proved to be straightforward. The primary ion/ion reaction channels were proton transfer, which does not lead to Au+ incorporation, and attachment of AuCl2- ions to the polypeptide cation, which does incorporate Au+. Fragmentation of the attachment product, the extent of which varied with peptide and charge state, led to losses of one or more molecules of HCl and, to some extent, cleavage of polypeptides at the disulfide linkage into its two constituent chains. Collisional activation of the intact metal-ion-incorporated peptides showed cleavage of the disulfide linkage to be a major, and in some cases exclusive, process. Cations with protons as the only cationizing agents showed only small contributions from cleavage of the disulfide linkage. These results indicate that Au+ incorporation into a disulfide-linked polypeptide ion is a promising way to effect selective dissocation of disulfide bonds. Cation switching via 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.