Statistical characterization of the charge state and residue dependence of low-energy CID peptide dissociation patterns
Statistical characterization of the charge state and residue dependence of low-energy CID peptide dissociation patterns
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DOI：
10.1021/ac0480949
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发表时间：
2005-09-15
影响因子：
7.4
通讯作者：
Wysocki, VH
中科院分区：
文献类型：
--
作者：
Huang, YY;Triscari, JM;Wysocki, VH
对28 330个独特的肽串联质谱进行数据挖掘，并以高置信度分配序列。通过根据相应肽的结构特征和电荷状态将光谱分成不同的集合，表征了促进气相肽中特定切割模式所涉及的化学相互作用。描述B和y离子在afl Xxx-Zzz残基组合处的裂解的成对片段化图显示，Arg和Lys之间的碱性差异导致单电荷Arg和Lys末端胰蛋白酶肽的不同解离模式。虽然一个主要的质子化形式（质子本地化）存在的Arg末端肽，不同的质子化形式或更容易的质子化形式（质子部分移动的）的相互转换的异质群体存在的赖氨酸末端肽。裂解C-末端至酸性残基主导了具有局部质子的单电荷肽的光谱，裂解N-末端至Pro主导了具有移动的或部分移动的质子的肽的光谱。当具有移动的或部分移动的质子的肽中不存在Pro时，每个肽键处的切割变得更加突出。上述模式是否可以在B离子、y离子或两者中找到取决于质子保持器在多重质子化肽中的位置。在来自具有可移动质子的肽的B和y离子以及来自具有部分可移动质子的肽的y离子中，观察到C-末端至支链脂肪族残基（Ile、瓦尔、Leu）的裂解增强;在来自具有部分移动的质子的肽的B离子中，观察到N-末端至这些残基的裂解增强。设计了统计工具，使碎裂图可视化，并测量它们之间的相似性。观察到的成对裂解模式扩展了我们对肽气相裂解行为的了解，并可能有助于采用改进模型预测碎片离子强度的算法开发。
Data mining was performed on 28 330 unique peptide tandem mass spectra for which sequences were assigned with high confidence. By dividing the spectra into different sets based on structural features and charge states of the corresponding peptides, chemical interactions involved in promoting specific cleavage patterns in gas-phase peptides were characterized. Pairwise fragmentation maps describing cleavages at afl Xxx-Zzz residue combinations for b and y ions reveal that the difference in basicity between Arg and Lys results in different dissociation patterns for singly charged Arg- and Lys-ending tryptic peptides. While one dominant protonation form (proton localized) exists for Arg-ending peptides, a heterogeneous population of different protonated forms or more facile interconversion of protonated forms (proton partially mobile) exists for Lys-ending peptides. Cleavage C-terminal to acidic residues dominates spectra from singly charged peptides that have a localized proton and cleavage N-terminal to Pro dominates those that have a mobile or partially mobile proton. When Pro is absent from peptides that have a mobile or partially mobile proton, cleavage at each peptide bond becomes much more prominent. Whether the above patterns can be found in b ions, y ions, or both depends on the location of the proton holder(s) in multiply protonated peptides. Enhanced cleavages C-terminal to branched aliphatic residues (Ile, Val, Leu) are observed in both b and y ions from peptides that have a mobile proton, as well as in y ions from peptides that have a partially mobile proton; enhanced cleavages N-terminal to these residues are observed in b ions from peptides that have a partially mobile proton. Statistical tools have been designed to visualize the fragmentation maps and measure the similarity between them. The pairwise cleavage patterns observed expand our knowledge of peptide gas-phase fragmentation behaviors and may be useful in algorithm development that employs improved models to predict fragment ion intensities.