Evidence for ionization-related conformational differences of peptide ions in a quadrupole ion trap.
Evidence for ionization-related conformational differences of peptide ions in a quadrupole ion trap.
复制标题
四极离子阱中肽离子与电离相关的构象差异的证据。
DOI：
10.1016/s1044-0305(01)00325-7
复制
发表时间：
2001
影响因子：
3.2
通讯作者：
Glish,GL
中科院分区：
文献类型：
--
作者：
Danell,AS;Glish,GL
已经研究了由两种不同的电离技术（纳流电喷雾电离（nanoESI）和液体二次离子质谱（LSIMS））产生的肽离子的边界激活解离（BAD）起始的差异。测定这些离子的BAD起始以比较离子的相对内能。通过nanoESI形成的质子化肽离子具有比通过LSIMS形成的离子更低的BAD起始。对于通过nanoESI产生的肽，衍生为在N-末端具有固定电荷的肽的BAD起始也低于通过LSIMS产生的肽。通过nanoESI形成的离子的BAD起始不随门控离子进入离子阱后和分离离子后解离前的碰撞冷却时间的变化而变化，这表明通过两种电离技术形成的离子不会采用相同的能量分布。有人提出，由这两种技术形成的离子在二级结构上不同，并且LSIMS离子被碰撞冷却到比nanoESI离子更低的局部最小值沿着势能表面。通过两种技术形成的离子显示出相同的解离模式，因此假设解离所需的绝对能量相同，LSIMS离子具有更高的解离临界能量。这导致观察到较高的BAD发作。
The differences in boundary-activated dissociation (BAD) onsets have been investigated for peptide ions that were generated by two different ionization techniques, nanoflow electros-pray ionization (nanoESI) and liquid secondary-ion mass spectrometry (LSIMS). BAD onsets of these ions were determined to compare the relative internal energies of the ions. Protonated peptide ions formed by nanoESI had lower BAD onsets than ions formed by LSIMS. The BAD onsets of peptides derivatized to have a fixed charge on the N-terminus also were lower for those generated by nanoESI than those generated by LSIMS. The BAD onsets of ions formed by nanoESI did not change with the variation of collisional cooling periods after gating ions into the ion trap and after isolating them prior to dissociation, indicating that the ions formed by the two ionization techniques would not adopt the same energy distributions. It is proposed that the ions formed by the two techniques differ in secondary structure, and the LSIMS ions are collisionally cooled to a lower local minimum along the potential energy surface than the nanoESI ions. Ions formed by both techniques show the same dissociation patterns, so assuming the absolute energy required for dissociation is the same, the LSIMS ions possess a higher critical energy of dissociation. This leads to the observation of the higher BAD onset.