Boue SM, Cole RB
Department of Chemistry, University of New Orleans, Louisiana 70148, USA.
J Mass Spectrom. 2000 Mar;35(3):361-8. doi: 10.1002/(SICI)1096-9888(200003)35:3<361::AID-JMS943>3.0.CO;2-D.
Electrospray ionization (ESI) combined with tandem mass spectrometry (MS/MS) was utilized for the structural confirmation of lipid A derived from Enterobacter agglomerans, a Gram-negative bacterium commonly found in field cotton. Previous ESI-MS studies conducted in our laboratory found that similarities exist between the fatty acid side-chains in the lipid A of E. agglomerans and that of Salmonella minnesota. It was noted that heterogeneity at the fatty acyl chain at position 3' of the diglucosamine backbone of E. agglomerans can take the form of either a myristyloxymyristyl group or, less commonly, a hydroxymyristyloxymyristyl moiety. In this work, tandem mass spectra obtained from heptaacyl and hexaacyl lipid A precursors derived from E. agglomerans and a known standard S. minnesota were compared to assist in structural elucidation. These ESI-MS/MS experiments confirmed the previously reported structure for lipid A derived from E. agglomerans. Moreover, MS/MS data indicated that the additional hydroxyl group of the 3'-position hydroxymyristyloxymyristyl moiety is present as the alpha-isomer.
电喷雾电离（ESI）与串联质谱（MS/MS）联用，用于对成团肠杆菌（一种常见于田间棉花的革兰氏阴性菌）来源的脂多糖A进行结构确证。此前我们实验室进行的ESI-MS研究发现，成团肠杆菌脂多糖A的脂肪酸侧链与明尼苏达沙门氏菌的脂肪酸侧链存在相似性。值得注意的是，成团肠杆菌二葡糖胺主链3'位的脂肪酰链存在异质性，其形式可以是十四烷氧基十四烷基基团，或者较少见的羟基十四烷氧基十四烷基部分。在这项工作中，将成团肠杆菌和已知标准菌株明尼苏达沙门氏菌来源的七酰基和六酰基脂多糖A前体获得的串联质谱进行比较，以辅助结构解析。这些ESI-MS/MS实验证实了此前报道的成团肠杆菌来源脂多糖A的结构。此外，MS/MS数据表明，3'-位羟基十四烷氧基十四烷基部分的额外羟基以α-异构体形式存在。
