Structural characterization of glycerophospholipids by combinations of ozone- and collision-induced dissociation mass spectrometry: the next step towards "top-down" lipidomics
Structural characterization of glycerophospholipids by combinations of ozone- and collision-induced dissociation mass spectrometry: the next step towards "top-down" lipidomics
复制标题
DOI：
10.1039/c3an01712e
复制
发表时间：
2014-01-01
期刊：
影响因子：
4.2
通讯作者：
Blanksby, Stephen J.
中科院分区：
文献类型：
--
作者：
Pham, Huong T.;Maccarone, Alan T.;Blanksby, Stephen J.
仅使用质谱学对包括甘油磷脂在内的复杂脂类进行完整的结构鉴定是对现代分析技术的重大挑战。在这里，我们证明了由磷脂的[M+Na](+)加合离子的碰撞诱导解离(CID)产生的产物离子可以被分离出来，并在线性离子陷阱质谱仪中进行随后的气相臭氧分解--称为臭氧诱导解离(OZID)。由此产生的CID/OzID实验产生了丰富的产物离子，这些离子是甘油主链上的酰基取代的特征(即，sn位)。这种方法可以区分SN位置的异构体，例如PC 16：0/18：1和PC 18：1/16：0的区域异构体磷脂酰胆碱对。重要的是，CID/OzID为给定样品中是否存在同分异构体混合物提供了一个灵敏的诊断方法。这对于组织提取物的分析具有非常高的价值，因为CID/OzID分析可以揭示即使在同一动物的不同组织中，异构体成分的相对丰度的变化。最后，我们演示了通过将后续的CID和/或OzID步骤添加到工作流程中，将碳-碳双键位置分配给特定主干位置上的单个酰基链的能力，并且这可以使用混合的三重四极-线性离子陷阱质谱仪在单一步骤中实现。这一独特的方法代表了迄今为止最完整和最具体的脂类质谱学结构分析，是迈向全面自上而下脂类组学的重要一步。
The complete structural elucidation of complex lipids, including glycerophospholipids, using only mass spectrometry represents a major challenge to contemporary analytical technologies. Here, we demonstrate that product ions arising from the collision-induced dissociation (CID) of the [M + Na](+) adduct ions of phospholipids can be isolated and subjected to subsequent gas-phase ozonolysis - known as ozone-induced dissociation (OzID) - in a linear ion-trap mass spectrometer. The resulting CID/OzID experiment yields abundant product ions that are characteristic of the acyl substitution on the glycerol backbone (i.e., sn-position). This approach is shown to differentiate sn-positional isomers, such as the regioisomeric phosphatidylcholine pair of PC 16:0/18:1 and PC 18:1/16:0. Importantly, CID/OzID provides a sensitive diagnostic for the existence of an isomeric mixture in a given sample. This is of very high value for the analysis of tissue extracts since CID/OzID analyses can reveal changes in the relative abundance of isomeric constituents even within different tissues from the same animal. Finally, we demonstrate the ability to assign carbon-carbon double bond positions to individual acyl chains at specific backbone positions by adding subsequent CID and/or OzID steps to the workflow and that this can be achieved in a single step using a hybrid triple quadrupole-linear ion trap mass spectrometer. This unique approach represents the most complete and specific structural analysis of lipids by mass spectrometry demonstrated to date and is a significant step towards comprehensive top-down lipidomics.