Matrix-Assisted Nanoelectrospray Mass Spectrometry for Soft Ionization of Metal(I)-Protein Complexes
Matrix-Assisted Nanoelectrospray Mass Spectrometry for Soft Ionization of Metal(I)-Protein Complexes
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基质辅助纳电喷雾质谱法用于金属 (I)-蛋白质复合物的软电离
DOI：
10.1039/c9an02117e
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发表时间：
2020
期刊：
影响因子：
4.2
通讯作者：
Zhiping Zhang
中科院分区：
文献类型：
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作者：
Jin Li;Yajun Zheng;Jia Zhao;Daniel E. Austin;Zhiping Zhang
金属离子在生物过程中起着重要的作用，金属-蛋白质相互作用的研究为了解金属离子在这类系统中的功能提供了基础。在当前的研究中，开发了一种新的基质辅助纳米电喷雾电离质谱（MANESI-MS）方法来研究金属离子之间的相互作用（即，Cu+）和蛋白质分子（即，肌红蛋白）。结果表明，本方法不仅是一种有效的策略，用于产生各种配合物与单价金属离子，如Cu+，其中没有观察到Cu+和Cu 2+之间的氧化还原转换，但也允许产生的Cu+-肌红蛋白复合物的较软的电离相比，肌红蛋白分子与传统的nanoESI。几个参数（即，发现肌红蛋白样品和Cu纳米颗粒溶液的混合模式、Cu颗粒的尺寸、Cu物质的氧化态和肌红蛋白溶液的酸度）在确定MANESI方法的电离效率中是至关重要的。首先将Cu纳米颗粒溶液加载到电喷雾尖端中，然后将肌红蛋白溶液加载到电喷雾尖端中，导致所产生的Cu+离子与肌红蛋白分子之间的有利相互作用，其中Cu颗粒的较小尺寸和金属物种的较低氧化态（Cu > Cu 2 O> CuO）给出较低的平均电荷态，因此所得Cu+-肌红蛋白复合物的电离较软，这可能是由于Cu+络合物的变性作用降低。的MANESI方法也已成功地被用来取代铜+和其他生物分子，如细胞色素c和血管紧张素II之间的配合物，虽然一个例外，发现溶菌酶，这表明电荷状态的增加。与Cu的研究类似，探索了各种其他金属纳米颗粒（Ni、Fe、W、Ag、Al、Zn和Co）以研究它们与肌红蛋白的相互作用，但只有Zn和Co可以产生单价金属离子（即，Zn+和Co+），随后与肌红蛋白的有利的相互作用，以及所得到的复合物的软电离。
Metal ions play significant roles in biological processes, and investigation of metal–protein interactions provides a basis to understand the functions of metal ions in such systems. In the current study, a novel matrix-assisted nanoelectrospray ionization mass spectrometry (MANESI-MS) method was developed for investigating the interactions between metal ions (i.e., Cu+) and protein molecules (i.e., myoglobin) using Cu nanoparticles as the matrix. The results demonstrated that the present method not only was an efficient strategy for the generation of various complexes with monovalent metal ions, such as Cu+, in which no redox transitions between Cu+ and Cu2+ were observed, but also allowed a softer ionization of the generated Cu+–myoglobin complexes compared to that of myoglobin molecules with conventional nanoESI. Several parameters (i.e., the mixing mode of the myoglobin sample and Cu nanoparticle solution, size of the Cu particle, oxidation state of the Cu species, and acidity of the myoglobin solution) were found to be crucial in determining the ionization efficiency of the MANESI method. First loading a Cu nanoparticle solution into the electrospray tip followed by a myoglobin solution resulted in a favorable interaction between the generated Cu+ ions and myoglobin molecules, in which a smaller size of the Cu particle and a lower oxidation state of the metal species (Cu > Cu2O > CuO) gave a lower average charge state and hence a softer ionization of the resulting Cu+–myoglobin complexes, possibly due to the reduced denaturing effects of the Cu+ complex. The MANESI method has also been successfully used to ionize the complexes between Cu+ and other biological molecules such as cytochrome c and angiotension II, although an exception was found for lysozymes, which show an increase in the charge state. Analogous to the study with Cu, a variety of other metal nanoparticles (Ni, Fe, W, Ag, Al, Zn and Co) were explored to study their interactions with myoglobin, but only Zn and Co could produce monovalent metal ions (i.e., Zn+ and Co+) followed by a favorable interaction with myoglobin, and a soft ionization of the resulting complexes.