CHAR OF CARDIOLIPIN BY TQ & MSQ ION-TRAP MASS SPEC WITH ELECTROSPRAY IONIZ

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们报道了负离子电喷雾串联质谱法用于表征心磷脂(CL)的结构。心磷脂是一种含有两个不同磷脂酰基的四酰基链磷脂，其甘油骨架上的脂肪酸残基的结构归属以前从未被用低能CAD串联质谱仪描述过。[M-H]和[M-2H]2-离子的低能MS2谱为化学发光性质的表征提供了完整的结构信息。[M-H]-离子的MS2光谱包含两组突出的碎片离子，其中包括一个磷脂酸、一个脱水磷脂酰甘油和一个(磷脂酸+136)阴离子。在[M-H]-离子的MS2光谱中观察到的两个不同的磷脂阴离子丰度的显著差异导致了中心甘油1‘或3’位置上的磷脂酰基部分的归属。在进一步的碰撞解离后，磷脂阴离子的MS3光谱提供了识别脂肪酰基取代基及其在甘油主干中的位置的信息。用TSQ或ITMS得到的[M-2H]2-离子的MS2谱包含了确认结构归属的补充信息。本文还介绍了上述方法在心磷脂异构体鉴别和多分子结构复杂心磷脂种类鉴定中的应用。

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. We report negative-ion electrospray tandem mass spectrometric methods for structural characterization of cardiolipin (CL), a four-acyl-chain phospholipid containing two distinct phosphatidyl moieties, of which structural assignment of the fatty acid residues attached to the glycerol backbones performed by low-energy CAD tandem mass spectrometry has not been previously described. The low-energy MS2-spectra of the [M - H]- and [M - 2H]2- ions obtained with ion-trap or with tandem quadrupole instrument combined with ion-trap MS3-spectra or with source CAD product-ion spectra provide complete structural information for CL characterization. The MS2-spectra of the [M - H]- ions contain two sets of prominent fragment ions that comprise a phosphatidic acid, a dehydrated phosphatidylglycerol, and a (phosphatidic acid + 136) anion. The substantial differences in the abundances of the two distinct phosphatidic anions observed in the MS2-spectra of the [M - H]- ions lead to the assignment of the phosphatidyl moieties attached to the 1' or 3' position of central glycerol. Upon further collisional dissociation, the MS3-spectra of the phosphatidic anions provide information to identify the fatty acyl substituents and their position in the glycerol backbone. The MS2-spectra of the [M - 2H]2- ions obtained with TSQ or ITMS contain complementary information to confirm structural assignment. The applications of the above methods in the differentiation of cardiolipin isomers and in the identification of complex cardiolipin species consisting of multiple molecular structures are also demonstrated.