Charge Manipulation Using Solution and Gas-Phase Chemistry to Facilitate Analysis of Highly Heterogeneous Protein Complexes in Native Mass Spectrometry.
Charge Manipulation Using Solution and Gas-Phase Chemistry to Facilitate Analysis of Highly Heterogeneous Protein Complexes in Native Mass Spectrometry.
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DOI：
10.1021/acs.analchem.0c05249
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发表时间：
2021-02-23
影响因子：
7.4
通讯作者：
Kaltashov IA
中科院分区：
文献类型：
--
作者：
Yang Y;Niu C;Bobst CE;Kaltashov IA
结构异质性是电喷雾电离质谱仪(ESI-MS)对含有结构异质生物聚合物的非共价络合物进行分析的一个重大挑战。这些物种表现出的广泛的质量分布不可避免地产生了代表不同电荷状态的重叠的离子信号，导致了没有可用于分配离子电荷和计算其质量的可识别特征的连续谱。这个问题可以通过使用有限电荷减少来规避，它利用气相化学反应在窄m/z窗口内选择的离子群内诱导电荷转移反应，从而产生定义明确且易于解释的电荷梯形。然而，天然MS中的离子信号通常存在于高m/z的质谱区，这往往超出了大多数商用质谱仪的前体离子隔离限制。虽然单链蛋白质的离子信号可以通过简单地切换到变性溶剂来转移到较低的m/z区，但这种方法不能应用于非共价组装体，因为它们在变性条件下固有的不稳定性。这项工作中探索的另一种方法依赖于向蛋白质溶液中添加增压试剂，作为一种在不影响其完整性的情况下增加ESI MS中非共价复合体的多次充电程度的方法。这将离子信号沿m/z尺度向下移动到通过前端四极杆可以容易地完成离子选择和隔离的区域，随后是隔离离子群体的有限电荷减少。利用结构不均匀的结合珠蛋白与血红蛋白形成的非共价复合体证明了新方法的可行性。
Structural heterogeneity is a significant challenge complicating (and in some cases making impossible) electrospray ionization mass spectrometry (ESI MS) analysis of non-covalent complexes comprising structurally heterogeneous biopolymers. The broad mass distribution exhibited by such species inevitably gives rise to overlapping ionic signals representing different charge states, resulting in a continuum spectrum with no discernable features that can be used to assign ionic charges and calculate their masses. This problem can be circumvented by using limited charge reduction, which utilizes gas-phase chemistry to induce charge-transfer reactions within ionic populations selected within narrow m/z windows, thereby producing well-defined and readily interpretable charge ladders. However, the ionic signal in native MS typically populates high m/z regions of mass spectra, which frequently extend beyond the precursor ion isolation limits of most commercial mass spectrometers. While the ionic signal of single-chain proteins can be shifted to lower-m/z regions simply by switching to a denaturing solvent, this approach cannot be applied to non-covalent assemblies due to their inherent instability under denaturing conditions. An alternative approach explored in this work relies on adding supercharging reagents to protein solutions as a means of increasing the extent of multiple charging of non-covalent complexes in ESI MS without compromising their integrity. This shifts the ionic signal down the m/z scale to the region where ion selection and isolation can be readily accomplished with a front-end quadrupole, followed by limited charge reduction of the isolated ionic population. The feasibility of the new approach is demonstrated using non-covalent complexes formed by hemoglobin with structurally heterogeneous haptoglobin.
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DOI：
10.1007/s13361-014-0965-1
发表时间：
2014-10
影响因子：
3.2
作者：
Loo, Rachel R. Ogorzalek;Lakshmanan, Rajeswari;Loo, Joseph A.
通讯作者：
Loo, Joseph A.
影响因子：
7.4
作者：
MCLUCKEY, SA;GOERINGER, DE
通讯作者：
GOERINGER, DE
影响因子：
4.1
作者：
Dillon, TM;Bondarenko, PV;Ricci, MS
通讯作者：
Ricci, MS
影响因子：
2.9
作者：
Fatunmbi, Ololade;Abzalimov, Rinat R.;Kaltashov, Igor A.
通讯作者：
Kaltashov, Igor A.
影响因子：
2.3
作者：
Henriksen, J;Ringborg, LH;Roepstorrf, P
通讯作者：
Roepstorrf, P