COEXISTING STABLE CONFORMATIONS OF GASEOUS PROTEIN IONS
COEXISTING STABLE CONFORMATIONS OF GASEOUS PROTEIN IONS
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DOI：
10.1073/pnas.90.3.790
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发表时间：
1993-02-01
影响因子：
11.1
通讯作者：
MCLAFFERTY, FW
中科院分区：
文献类型：
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作者：
SUCKAU, D;SHI, Y;MCLAFFERTY, FW
为了进一步了解溶剂在蛋白质构象稳定中的作用，在真空中的蛋白质离子的结构和动力学性质已被探测在傅立叶变换质谱仪中的氢-氘交换。电喷雾电离五种蛋白质产生的多电荷离子在10（-7）Pa（1 Pa = 133.3 Pa）下与（H2O）-H2发生交换反应，表现出准一级动力学。相对于变性的S-衍生的RNA酶A，S-S交联的RNA酶A的气相紧密性分别由35和135个氢原子的交换表示。对于纯的细胞色素c离子，至少有三种不同的气体构象的存在是由显着不同的值-52，113，和74-的反应性H原子;观察这些相同的值的离子数-2，7，和5，分别不同的电荷状态表明构象不敏感库仑力。对于这些构象异构体中的每一种，由这些值表示的真空中的紧密度直接对应于溶液中的已知构象异构体结构的紧密度，从该溶液中通过电喷雾产生构象异构体离子。S-衍生的RNA酶A离子也以至少两种交换50-140个H原子的气态构象异构体存在。气态构象异构体离子在数小时内是异构稳定的;溶剂的去除大大增加了构象刚性。更具体的离子-分子反应可以提供构象异构体结构的进一步细节。
For further insight into the role of solvent in protein conformer stabilization, the structural and dynamic properties of protein ions in vacuo have been probed by hydrogen-deuterium exchange in a Fourier-transform mass spectrometer. Multiply charged ions generated by electrospray ionization of five proteins show exchange reactions with (H2O)-H-2 at 10(-7) torr (1 torr = 133.3 Pa) exhibiting pseudo-first-order kinetics. Gas-phase compactness of the S-S cross-linked RNase A relative to denatured S-derivatized RNase A is indicated by exchange of 35 and 135 hydrogen atoms, respectively. For pure cytochrome c ions, the existence of at least three distinct gaseous conformers is indicated by the substantially different values-52, 113, and 74-of reactive H atoms; the observation of these same values for ions of a number-2, 7, and 5, respectively-of different charge states indicates conformational insensitivity to coulombic forces. For each of these conformers, the compactness in vacuo indicated by these values corresponds directly to that of a known conformer structure in the solution from which the conformer ions are produced by electrospray. S-derivatized RNase A ions also exist as at least two gaseous conformers exchanging 50-140 H atoms. Gaseous conformer ions are isomerically stable for hours; removal of solvent greatly increases conformational rigidity. More specific ion-molecule reactions could provide further details of conformer structures.