Jin Lan, Barran Perdita E, Deakin Jon A, Lyon Malcolm, Uhrín Dusan
University of Edinburgh, School of Chemistry, Joseph Black Building, West Mains Rd., Edinburgh, UK EH9 3JJ.
Phys Chem Chem Phys. 2005 Oct 7;7(19):3464-71. doi: 10.1039/b508644b. Epub 2005 Aug 22.
We have performed conformational analyses of heparin-derived oligosaccharide ions in the gas phase using a combination of ion-mobility mass spectrometry and molecular modelling. Negative mode electrospray ionisation was used to generate singly (disaccharide, [C12H15NO19S3Na3]-) and doubly charged (tetrasaccharides, [C24H30N2O38S6Na6]2- and [C24H31N2O35S5Na5]2-) ions containing three and six Na+ ions, respectively. Good agreement was obtained between the experimental and theoretical cross sections. The latter were obtained using modelled structures generated by the AMBER-based force field. Analysis of the conformations of the oligosaccharide ions shows that sodium cations play a major role in stabilizing these ions in the gas phase. This was seen in the formation of oligomers of the disaccharide ion and "compact" structures of tetrasaccharide ions. Interestingly, the gas phase conformations of the three tetrasaccharide ions with different primary structures were significantly different.
我们使用离子淌度质谱和分子建模相结合的方法，对气相中肝素衍生的寡糖离子进行了构象分析。采用负离子模式电喷雾电离分别生成含三个和六个钠离子的单电荷（二糖，[C12H15NO19S3Na3]-）和双电荷（四糖，[C24H30N2O38S6Na6]2-和[C24H31N2O35S5Na5]2-）离子。实验和理论截面之间取得了良好的一致性。后者是使用基于AMBER力场生成的模型结构获得的。对寡糖离子构象的分析表明，钠离子在气相中稳定这些离子方面起主要作用。这在二糖离子寡聚体的形成和四糖离子的“紧凑”结构中可见。有趣的是，具有不同一级结构的三种四糖离子的气相构象有显著差异。
