FRAGMENTATION PROPERTIES OF OXIDIZED PEPTIDES BY ERGODIC & NON-ERGODIC METHODS

氧化肽的遍历断裂特性

• 批准号: 8168865
• 负责人: JOSHUA S SHARP
• 金额: $ 3.37万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-10 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8168865
• 关键词: Acids; Affect; Amino Acids; Characteristics; Charge; Chemistry; Computer Retrieval of Information on Scientific Projects Database; Coupled; Diagnostic; Dissociation; Electrons; Funding; Grant; Hydrolysis; Hydroxyl Radical; Institution; Ions; Isomerism; Methods; Modeling; Pattern; Peptides; Process; Property; Research; Research Personnel; Resources; Scanning; Side; Site; Source; United States National Institutes of Health; Work; mass spectrometer; oxidation; research study; tandem mass spectrometry

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Assignment of oxidation sites for hydroxyl radical footprinting experiments is done by means of tandem mass spectrometry, where the oxidized peptide is activated in the mass spectrometer and the resulting fragmentation pattern is compared to a computed theoretical fragmentation pattern, and the differences analyzed to determine where the oxidation occurred. However, the oxidation of side chains alters the fragmentation chemistry in ergodic fragmentation methods, often resulting in a smaller number of fragmentation products which makes absolute assignment of sites of oxidation difficult. We are attempting to utilize higher energies for ergodic fragmentation, coupled with scanning at lower mass to charge ratios, to try to find characteristic side chain ions and side chain losses that are diagnostic of oxidation at a particular amino acid residue, in order to simplify the assignment of oxidation sites. Another difficulty that often arises is the matter of oxidation isomers; a peptide on which oxidation occurs at two or more sites. Quantitation of the rates of oxidation on each site is not possible by simply quantitating the abundances of fragment ions, as oxidation affects the pattern of fragmentation itself in ergodic processes. Recent work has suggested that non-ergodic fragmentation methods such as electron capture dissociation (ECD) are insensitive to side chain oxidation, suggesting that fragment ion abundances may be useful for quantitating isomeric mixtures of oxidized peptides. We will be oxidizing model peptides with multiple oxidation sites and studying the abundances of fragment ions generated by ECD. These abundances will be compared with the abundances of oxidized and unoxidized amino acids generated by acid hydrolysis of the oxidized peptide in order to determine if quantitation by ECD fragment ion abundance is feasible.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 羟基自由基足迹实验的氧化位点的分配是通过串联质谱法进行的，其中氧化肽在质谱仪中被激活，并将所得的片段化模式与计算的理论碎片模式进行比较，并分析了氧化的差异。 然而，侧链的氧化改变了厄乳片段化方法中的碎片化学，通常会导致较少数量的碎裂产物，从而使氧化位点的绝对分配变得困难。 我们正在尝试利用较高的能量来进行麦迪克的碎片化，并在较低的质量上扫描，以试图找到特定的侧链离子和特定氨基酸残基上氧化诊断的特征侧链损耗，以简化氧化位点的分配。 经常出现的另一个困难是氧化异构体的问题。在两个或多个位点发生氧化的肽。 通过简单地量化碎片离子的丰富度，不可能对每个位点的氧化速率进行定量，因为氧化会影响厄加德过程中的碎片本身。 最近的工作表明，诸如电子捕获解离（ECD）之类的非恋性碎片化方法对侧链氧化不敏感，这表明碎片离子丰度可能有助于定量氧化肽的异构体混合物。 我们将用多个氧化位点氧化模型肽，并研究ECD产生的片段离子的丰度。 这些丰度将与氧化肽的酸水解产生的氧化和非氧化氨基酸的丰度进行比较，以确定ECD片段足够的定量是否可行。