Chen Y L, Campbell J M, Collings B A, Konermann L, Douglas D J
Department of Chemistry, University of British Columbia, Vancouver, Canada.
Rapid Commun Mass Spectrom. 1998;12(15):1003-10. doi: 10.1002/(SICI)1097-0231(19980815)12:15<1003::AID-RCM275>3.0.CO;2-#.
Gas phase holomyoglobin (hMb) ions in charge states +7 to +21 were formed by electrospray ionization in combination with a continuous-flow mixing apparatus. Collision cross section measurements show that the highly charged ions are somewhat unfolded in comparison to low charge states but still retain a considerable degree of folding. A new collision model is presented which calculates the relative energies transferred to complexes in tandem mass spectrometry. Tandem mass spectrometry and ion trapping experiments both show that the energies required to dissociate heme from the highly charged heme-protein complexes in the gas phase are similar to those of low charge states, previously shown in literature ion cyclotron resonance experiments to be 0.7-1.0 eV. These energies are comparable to those of the heme binding energy in solution. The results suggest that even for the highly charged hMb ions which have unfolded somewhat, the heme-protein interactions remain relatively unperturbed.
通过电喷雾电离结合连续流动混合装置，形成了电荷态为+7至+21的气相全肌红蛋白（hMb）离子。碰撞截面测量表明，与低电荷态相比，高电荷离子有些展开，但仍保留相当程度的折叠。提出了一种新的碰撞模型，该模型计算串联质谱中转移到复合物的相对能量。串联质谱和离子阱实验均表明，在气相中从高电荷血红素 - 蛋白质复合物中解离血红素所需的能量与低电荷态相似，先前在文献离子回旋共振实验中显示为0.7 - 1.0 eV。这些能量与溶液中血红素结合能相当。结果表明，即使对于有些展开的高电荷hMb离子，血红素 - 蛋白质相互作用仍然相对未受干扰。
