Identification of amino acid epimerization and isomerization in crystallin proteins by tandem LC-MS.
Identification of amino acid epimerization and isomerization in crystallin proteins by tandem LC-MS.
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DOI：
10.1021/ac502296c
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发表时间：
2014-10-07
影响因子：
7.4
通讯作者：
Julian, Ryan R.
中科院分区：
文献类型：
--
作者：
Tao, Yuanqi;Julian, Ryan R.
不导致质量变化的翻译后修饰特别难以通过质谱法检测。例如，天冬氨酸的异构化或肽内任何手性残基的差向异构化不会导致质量偏移，但可以通过检查独立获得的串联质谱或通过与另一种技术组合来鉴定。对于生物样品的分析，这意味着必须使用液相色谱或一些其他类型的分离来首先将异构体彼此分离。此外，必须重复采样每个特定的感兴趣的m/z，以允许比较来自每个分离的异构体的串联质谱，这与蛋白质组学中的传统方法形成对比，在蛋白质组学中，目标通常是避免重复测定相同的m/z。我们举例说明，异构化和差向异构化的肽，可以确定在这种方式通过检查从绵羊眼透镜中提取的长寿晶体蛋白。使用串联质谱法（依赖于液相色谱分离后自由基定向解离（RDD）和碰撞诱导解离（CID）的组合）来鉴定修饰的肽。许多异构化和差向异构化的位点，包括几个以前没有被确定的，用肽特异性确定。它表明，每个肽内的氨基酸异构化的特定位点可以通过与合成肽的比较来确定。对于α-晶状体蛋白，经历最大程度异构化的位点对应于无序区域，这可能对衰老背景下的伴侣蛋白功能具有重要意义。
Post-translational modifications that do not result in a change in mass are particularly difficult to detect by mass spectrometry. For example, isomerization of aspartic acid or epimerization of any chiral residue within a peptide do not lead to mass shifts but can be identified by examination of independently acquired tandem mass spectra or by combination with another technique. For analysis of a biological sample, this means that liquid chromatography or some other type of separation must be used to first separate the isomers from one another. Furthermore, each specific m/z of interest must be sampled repeatedly to allow for comparison of the tandem mass spectra from each separated isomer, which contrasts with the traditional approach in proteomics where the goal is typically to avoid resampling the same m/z. We illustrate that isomerization and epimerization of peptides can be identified in this fashion by examination of long-lived crystallin proteins extracted from a sheep eye lens. Tandem mass spectrometry relying on a combination of radical directed dissociation (RDD) and collision induced dissociation (CID) following separation by liquid chromatography was used to identify modified peptides. Numerous sites of isomerization and epimerization, including several that have not been previously identified, were determined with peptide specificity. It is demonstrated that the specific sites of amino acid isomerization within each peptide can be identified by comparison with synthetic peptides. For α-crystallin proteins, the sites that undergo the greatest degree of isomerization correspond to disordered regions, which may have important implications on chaperone functionality within the context of aging.
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影响因子：
4.9
作者：
Ly, Tony;Zhang, Xing;Julian, Ryan R.
通讯作者：
Julian, Ryan R.
影响因子：
1.7
作者：
Brueckner, Christin;Bunz, Svenja-Catharina;Scriba, Gerhard K. E.
通讯作者：
Scriba, Gerhard K. E.
影响因子：
2
作者：
Fujii, N
通讯作者：
Fujii, N
影响因子：
7.4
作者：
Adams, CM;Zubarev, RA
通讯作者：
Zubarev, RA
通过离子迁移率光谱法含有（D）氨基酸的（D） - 氨基酸的位点特异性表征。
影响因子：
7.4
作者：
Jia, Chenxi;Lietz, Christopher B.;Yu, Qing;Li, Lingjun
通讯作者：
Li, Lingjun