Gas-phase bovine ubiquitin cation conformations resolved by gas-phase hydrogen/deuterium exchange rate and extent
Gas-phase bovine ubiquitin cation conformations resolved by gas-phase hydrogen/deuterium exchange rate and extent
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DOI：
10.1016/s1387-3806(98)14172-6
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发表时间：
1999-04-29
影响因子：
1.8
通讯作者：
Marshall, AG
中科院分区：
文献类型：
--
作者：
Freitas, MA;Hendrickson, CL;Marshall, AG
采用电喷雾电离傅里叶变换离子回旋共振（FT-ICR）质谱法研究了牛泛素中[M + nH](n+) （n = 5-13）离子与H/D交换试剂D2O气相氢/氘交换。通过存储波形傅里叶反变换激发分离出所有奇数或所有偶数电荷态，同时与泄漏到ICR池中的D2O稳定反应，反应周期为1 s ~ 1 h。根据h /D交换程度的不同，可以分辨出不同的气相蛋白质构象。5+和6+电荷态显示出广泛的构象分布，范围从0-80%氘掺入。相比之下，7-11+和13+这两个高电荷态显示出单一的主同位素分布，而12+电荷态则分成两个丰度相当的同位素分布。一般来说，H/D汇率随电荷状态的增加而降低。在观察7+电荷态的构象分布时，改变了外部电喷雾电离源条件（毛细管电流和外部积累时间）：在任何一个区域增加加热都会减少慢交换构象的数量。在9.4 T下，可以在相对较高的压力（2 × 10(-7) Torr）下捕获大量离子，反应时间长（长达1小时）。这些结果证明了FT-ICR质量分析在电喷涂蛋白质的气体H/D交换后分散不同气相蛋白质构象的能力，以便随后的分离酸表征。(C) 1999 Elsevier Science B.V.
The gas-phase hydrogen/deuterium exchange of [M + nH](n+) (n = 5-13) ions of bovine ubiquitin with the H/D exchange reagent D2O are examined by electrospray ionization Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. All of the odd or all of the even charge states were isolated by stored waveform inverse Fourier transform excitation and simultaneously reacted with D2O leaked steadily into the ICR cell for reaction periods ranging from 1 s to 1 h. Different gas-phase protein conformations could be resolved according to difference in extent of H/D exchange. The 5+ and 6+ charge states display broad distributions of conformations ranging from 0-80% deuterium incorporation. In contrast, each of the higher charge states, 7-11+ and 13+, displays a single major isotopic distribution, whereas the 12+ charge state separates into two isotopic distributions of comparable abundance. In general, H/D exchange rates decrease with increasing charge state. External electrospray ionization source conditions (capillary current and external accumulation period) were varied while observing the conformational distribution of the 7+ charge state: increased heating in either region reduced the number of slow-exchanging conformations. At 9.4 T, it is possible to trap a large number of ions for a long reaction period (up to 1 h) at relatively high pressure (2 x 10(-7) Torr). These results demonstrate the capability of FT-ICR mass analysis following gaseous H/D exchange of electrosprayed proteins to disperse different gas-phase protein conformations for subsequent isolation acid characterization. (C) 1999 Elsevier Science B.V.