Dissociations of disulfide-linked gaseous polypeptide/protein anions: Ion chemistry with implications for protein identification and characterization
Dissociations of disulfide-linked gaseous polypeptide/protein anions: Ion chemistry with implications for protein identification and characterization
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DOI：
10.1021/pr025561z
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发表时间：
2002-11-01
影响因子：
4.4
通讯作者：
McLuckey, SA
中科院分区：
文献类型：
--
作者：
Chrisman, PA;McLuckey, SA
包含二硫键的整个蛋白质阴离子的离子阱碰撞激活导致包含二硫键的键之一断裂。二硫键可以在三个可能位置中的任何一个断裂，产生几种具有不同硫原子分配的产物。在二硫键最近的 C-S 键裂解形成的产物中，在多肽主链处发生容易的第二代解离。这种裂解仅发生在半胱氨酸残基的 N 端侧，C-S 键从此处裂解，从而产生 c 和 z-S 型产物离子。该次级反应显然是相对低能量的反应，具有相对高的熵要求，因为在束型碰撞激活条件下观察不到它是主要过程，但在离子阱碰撞激活条件下是主要过程。这种切割的特异性，以及通过硫原子分布将其与其他切割区分开来的能力，使其可用于通过数据库搜索来识别未知蛋白质。此外，二硫键裂解模式可用于提供有关翻译后修饰位置的信息。给出了使用牛胰蛋白酶抑制剂和核糖核酸酶 A 和 B 的例子来说明这些观点。
Ion trap collisional activation of whole protein anions that contain disulfide bonds results in the cleavage of one of the bonds that comprises the disulfide linkage. The disulfide linkage can break at any of three possible locations, giving rise to several products with different partitioning of sulfur atoms. A facile second-generation dissociation occurs at the polypeptide backbone from products formed from cleavage of the nearest C-S bond of a disulfide linkage. This cleavage occurs exclusively at the N-terminal side of the cysteine residue, from which the C-S bond was cleaved, thereby yielding c and z-S type product ions. This secondary reaction is apparently a relatively low-energy reaction with relatively high entropy requirements because it is not observed to be a major process under beam-type collisional activation conditions, but is a major process under ion trap collisional activation conditions. The specificity of this cleavage, as well as the ability to distinguish it from other cleavages by the sulfur atom distribution, make it useful for the identification of unknown proteins via database searching. Furthermore, the pattern of disulfide cleavages can be useful in providing information about the location of post-translational modifications. Examples using bovine pancreatic trypsin inhibitor and ribonuclease A and B are given to illustrate these points.