Cross-validation of lipid structure assignment using orthogonal ion activation modalities on the same mass spectrometer

This data set accompanies the manuscript Cross-validation of lipid structure assignment using orthogonal ion activation modalities on the same mass spectrometer by Samuel C. Brydon, Berwyck L.J. Poad, Mengxuan Fang, Yepy H. Rustam, Reuben S.E. Young, Dmitri Mouradov, Oliver M. Sieber, Todd W. Mitchell, Gavin E. Reid,* Stephen J. Blanksby,* and David L. Marshall* (submitted to the Journal of the American Society for Mass Spectrometry).

Abstract: The onset and progression of cancer is associated with changes in the composition of the lipidome. Therefore, better understanding of the molecular mechanisms of these disease states requires detailed structural characterization of the individual lipids within the complex cellular milieu. Recently, changes in the unsaturation profile of membrane lipids have been observed in cancer cells and tissues, but assigning the position(s) of carbon-carbon double bonds in fatty acyl chains carried by membrane phospholipids, including the resolution of lipid regioisomers, has proven analytically challenging. Conventional tandem mass spectrometry approaches based on collision-induced dissociation of ionized glycerophospholipids do not yield spectra that are indicative of the location(s) of carbon-carbon double bonds. Ozone-induced dissociation (OzID) and ultraviolet photodissociation (UVPD) have emerged as alternative ion activation modalities wherein diagnostic product ions can enable de novo assignment of position(s) of unsaturation based on predictable fragmentation behaviors. Here, for the first time, OzID and UVPD (193 nm) mass spectra are acquired on the same mass spectrometer to evaluate the relative performance of the two modalities for lipid identification and to interrogate the respective fragmentation pathways under comparable conditions. Based on investigations of lipid standards, fragmentation rules for each technique are expanded to increase confidence in structural assignments and exclude potential false positives. Parallel application of both methods to unsaturated phosphatidylcholines extracted from isogenic colorectal cancer cell lines provides high confidence in the assignment of multiple double bond isomers in these samples and cross-validates relative changes in isomer abundance.

Data file includes: experimental mass spectra files

本数据集伴随论文《在相同质谱仪上通过正交离子激活模式交叉验证脂质结构归属》的发表，该论文由Samuel C. Brydon、Berwyck L.J. Poad、Mengxuan Fang、Yepy H. Rustam、Reuben S.E. Young、Dmitri Mouradov、Oliver M. Sieber、Todd W. Mitchell、Gavin E. Reid、Stephen J. Blanksby和David L. Marshall共同撰写，并已提交至《美国质谱学会杂志》。

摘要：癌症的发生与发展与脂质体的组成变化密切相关。因此，深入了解这些疾病状态分子机制，需要详细解析复杂细胞环境中个体脂质的结构特征。近期，研究者观察到癌细胞和组织中膜脂的不饱和度谱发生变化，然而，对于膜磷脂携带的脂肪酸链上碳-碳双键位置的归属，包括脂质区域异构体的解析，分析上一直颇具挑战。基于碰撞诱导解离的离子化甘油磷脂的常规串联质谱方法并未产生能够指示碳-碳双键位置的谱图。臭氧诱导解离（OzID）和紫外光解离（UVPD）已作为替代的离子激活模式出现，其中诊断性产物离子能够基于可预测的裂解行为，实现基于新方法的不饱和度位置的重新归属。在本研究中，首次在同一质谱仪上获得了OzID和UVPD（193 nm）质量光谱，以评估两种模式的相对性能，并比较在相似条件下各自的裂解路径。基于脂质标准的研究，针对每种技术扩展了裂解规则，以增强结构归属的信心并排除潜在的假阳性。将两种方法平行应用于从同源结直肠癌细胞系中提取的不饱和磷脂酰胆碱，对这些样本中多个双键异构体的归属提供了高置信度，并验证了异构体丰度的相对变化。

数据文件包括：实验质量光谱文件。