Electrospray ionization multiple stage quadrupole ion-trap and tandem quadrupole mass spectrometric studies on phosphatidylglycerol from Arabidopsis leaves
Electrospray ionization multiple stage quadrupole ion-trap and tandem quadrupole mass spectrometric studies on phosphatidylglycerol from Arabidopsis leaves
复制标题
DOI：
10.1016/j.jasms.2006.12.012
复制
发表时间：
2007-04-01
影响因子：
3.2
通讯作者：
Welti, Ruth
中科院分区：
文献类型：
--
作者：
Hsu, Fong-Fu;Turk, John;Welti, Ruth
磷酸甘油（PG）是植物叶绿体的主要磷脂。来自拟南芥的 PG 在主要 18:3 /Delta(3)16:1-PG 物种的 sn-2 位置以及 18:2/Delta(3)16:1-PG 和 16:0 /Delta(3)16:1-PG 中具有不寻常的脂肪酰基链 3-反式十六烯酰基 (Delta(3)16:1)。在串联四极杆或离子阱质谱仪中进行低能碰撞激活解离 (CAD) 时，含有 Delta(3)16:1 物质的 PG 分子的 [M - H](-) 离子给出的产物离子光谱很容易与不含 Delta(3)16:1 物质的 PG 产生的光谱区分开来。含有 Delta(3)16:1-脂肪酰基的 PG 通过 MS2 产物离子质谱进行表征，其中包含由于失去乙烯酮 Delta(3)16:1-脂肪酰基取代基而产生的主要 [M - H - 236](-) 离子。这是由于参与烯酮损失的Delta(3)16:1-脂肪酸取代基的α-氢是烯丙基氢，其非常不稳定。这导致 236 优先中性损失，而 254 中性损失（即作为脂肪酸损失）急剧下降，这些独特特征表明存在含有 PG 的 Delta(3)16:1-脂肪酰基。因此，236 的中性丢失扫描提供了一种灵敏的串联四极杆质谱方法来鉴定脂质混合物中含有 Delta(3)16:1 的 PG 物质。这种低能串联质谱方法还可以揭示由两种异构体结构组成的拟南芥 PG 的结构。
Phosphaticlylglycerol (PG) is the major phospholipid of plant chloroplasts. PG from Arabidopsis thaliana has an unusual fatty acyl chain, 3-trans-hexadecenoyl (Delta(3)16:1) in the sn-2 position of the major 18:3 /Delta(3)16:1-PG species, as well as in 18:2/Delta(3)16:1-PG and 16:0 /Delta(3)16:1-PG. Upon low-energy collisionally activated dissociation (CAD) in a tandem quadrupole or in an ion-trap mass spectrometer, the [M - H](-) ions of the PG molecules containing Delta(3)16:1 give product-ion spectra that are readily distinguishable from those arising from PGs without the Delta(3)16:1 species. The Delta(3)16:1-fatty acyl-containing PGs are characterized by MS2 product-ion mass spectra that contain predominant [M - H - 236](-) ions arising from loss of the Delta(3)16:1-fatty acyl substituent as a ketene. This is attributable to the fact that the alpha-hydrogen of the Delta(3)16:1-fatty acid substituent involved in the ketene loss is an allylic hydrogen, which is very labile. This leads to preferential neutral loss of 236 and drastic decline in the neutral loss of 254 (i.e., loss as a fatty acid), the unique features that signify the presence of Delta(3)16:1-fatty acyl containing PGs. The neutral loss scan of 236, thus, provides a sensitive tandem quadrupole mass spectrometric means to identify Delta(3)16:1-containing PG species in lipid mixtures. This low-energy tandem mass spectrometric approach also permits the structures of the Arabidopsis PGs that consist of two isomeric structures to be unveiled.