Cheng X, Camp D G, Wu Q, Bakhtiar R, Springer D L, Morris B J, Bruce J E, Anderson G A, Edmonds C G, Smith R D
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
Nucleic Acids Res. 1996 Jun 1;24(11):2183-9. doi: 10.1093/nar/24.11.2183.
Ionization and molecular weight (MW) determination of megadalton size plasmid DNA has been achieved using electrospray ionization (ESI) with Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. DNA molecules were shown to remain intact through electrospray ionization by collection on a specially prepared surface, followed by agarose gel electrophoresis. Individual highly charged ions of plasmid DNA produced by ESI were trapped in an FTICR cell for up to several hours and reacted with acetic acid to induce charge state shifts. Measurements of mass-to-charge ratios for these multiple peaks arising from charge state shifting give MW measurements of individual ions with an average accuracy of 0.2%. The MW distribution was obtained by measurements for a number of individual ions from the same sample [plasmid DNA: pGEM-5S MW(cal) = 1.946 MDa], yielding a MW(obs) of 1.95 +/- 0.07 MDa for ions clustered in the vicinity of the expected MW.
利用电喷雾电离（ESI）结合傅里叶变换离子回旋共振（FTICR）质谱法，已实现了对百万道尔顿大小质粒DNA的电离和分子量（MW）测定。通过在特制表面上收集，DNA分子经电喷雾电离后仍保持完整，随后进行琼脂糖凝胶电泳。ESI产生的质粒DNA单个高电荷离子被捕获在FTICR池中长达数小时，并与乙酸反应以诱导电荷态变化。对电荷态变化产生的这些多个峰的质荷比测量给出了单个离子的MW测量值，平均准确度为0.2%。通过对来自同一样品（质粒DNA：pGEM-5S MW（计算值）= 1.946 MDa）的多个单个离子进行测量获得MW分布，对于聚集在预期MW附近的离子，得到的MW（观测值）为1.95±0.07 MDa。
